build(deps): bump grpc from 1.73.0 to 1.74.0

Bumps `grpc` from 1.73.0 to 1.74.0.

Updates `io.grpc:grpc-core` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-netty` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-protobuf` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-stub` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-grpclb` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-inprocess` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

Updates `io.grpc:grpc-util` from 1.73.0 to 1.74.0
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](https://github.com/grpc/grpc-java/compare/v1.73.0...v1.74.0)

---
updated-dependencies:
- dependency-name: io.grpc:grpc-core
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-netty
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-protobuf
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-stub
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-grpclb
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-inprocess
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.grpc:grpc-util
  dependency-version: 1.74.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -15,13 +15,11 @@ assignees: ''
 A clear and concise description of what the bug is.
 
 **To Reproduce**
-Steps or reproducer to reproduce the behavior. 
-This section *must* be provided, if not, the issue may not get attention.
+Steps or reproducer to reproduce the behavior in a form of a unit test.
+This section *must* be provided, if not, the issue may not get attention since the maintainers have very limited capacity.
 
 **Expected behavior**
 A clear and concise description of what you expected to happen.
 
 **Additional context**
 Add any other context about the problem here.
-
-

.github/dependabot.yml

@@ -1,11 +1,18 @@
 version: 2
 updates:
-- package-ecosystem: maven
-  directory: "/"
-  schedule:
-    interval: daily
-  open-pull-requests-limit: 10
-  ignore:
-  - dependency-name: org.codehaus.plexus:plexus-compiler-javac-errorprone
-    versions:
-    - "> 2.8.6, < 2.9"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: daily
+      time: "19:30"
+      timezone: Europe/Paris
+  - package-ecosystem: "gradle"
+    directory: "/"
+    schedule:
+      interval: daily
+      time: "19:30"
+      timezone: Europe/Paris
+    labels:
+      - area/dependencies
+    ignore:
+      - dependency-name: com.google.protobuf:protoc

.github/workflows/build-main.yml

@@ -1,5 +1,5 @@
 #
-# Copyright 2016-2021 The jetcd authors
+# Copyright 2016-2023 The jetcd authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -14,10 +14,10 @@
 # limitations under the License.
 #
 
-name: Build and Publish
+name: Build and Publish (Snapshot)
 
 concurrency:
-  group: ${{ github.ref }}-${{ github.workflow }}
+  group: ${{ github.workflow }}-${{ github.sha }}
   cancel-in-progress: true
 
 on:
@@ -25,23 +25,52 @@ on:
     branches:
       - main
   workflow_dispatch:
+  schedule:
+  - cron: "0 0 * * *"
 
 jobs:
+  checks:
+    uses: ./.github/workflows/checks.yml
+
   build:
+    needs:
+      - checks
+    strategy:
+      matrix:
+        java-version:
+          - 11
+          - 17
+          - 21
+        etcd:
+          - quay.io/coreos/etcd:v3.5.21
+          - quay.io/coreos/etcd:v3.6.0
+    uses: ./.github/workflows/build.yml
+    with:
+      javaVersion: "${{ matrix.java-version }}"
+      etcdImage: "${{ matrix.etcd }}"
+
+  publish:
     runs-on: ubuntu-latest
+    needs:
+      - build
     steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Set Up Java
-        uses: actions/setup-java@v2
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: 'Set Up Java'
+        uses: actions/setup-java@v4
         with:
           java-version: 11
           distribution: 'temurin'
-      - name: Build Project
-        env:
-          OSSRH_USERNAME: ${{ secrets.OSSRH_USERNAME }}
-          OSSRH_PASSWORD: ${{ secrets.OSSRH_PASSWORD }}
+          cache: 'gradle'
+      - name: 'Collect Info'
+        run: |
+          ./gradlew currentVersion
+      - name: 'Publish Snapshot'
+        if: github.event_name != 'schedule'
+        env:
+          NEXUS_USERNAME: ${{ secrets.OSSRH_USERNAME }}
+          NEXUS_PASSWORD: ${{ secrets.OSSRH_PASSWORD }}
         run: |
-          ./gradlew spotlessCheck
-          ./gradlew test
           ./gradlew publishToSonatype -Prelease.forceSnapshot

.github/workflows/build-pr.yml

@@ -1,5 +1,5 @@
 #
-# Copyright 2016-2021 The jetcd authors
+# Copyright 2016-2023 The jetcd authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,9 +17,12 @@
 name: Build PR
 
 concurrency:
-  group: ${{ github.ref }}-${{ github.workflow }}
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
   cancel-in-progress: true
 
+permissions:
+  contents: read
+
 on:
   pull_request:
     branches:
@@ -27,17 +30,22 @@ on:
   workflow_dispatch:
 
 jobs:
+  checks:
+    uses: ./.github/workflows/checks.yml
+
   build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Set Up Java
-        uses: actions/setup-java@v2
-        with:
-          java-version: 11
-          distribution: 'temurin'
-      - name: Build Project
-        run: |
-          ./gradlew spotlessCheck
-          ./gradlew test
+    needs:
+      - checks
+    strategy:
+      matrix:
+        java-version:
+          - 11
+          - 17
+          - 21
+        etcd:
+          - quay.io/coreos/etcd:v3.5.21
+          - quay.io/coreos/etcd:v3.6.0
+    uses: ./.github/workflows/build.yml
+    with:
+      javaVersion: "${{ matrix.java-version }}"
+      etcdImage: "${{ matrix.etcd }}"

.github/workflows/build.yml

@@ -0,0 +1,33 @@
+name: Build
+
+on:
+  workflow_call:
+    inputs:
+      javaVersion:
+        required: true
+        type: string
+      etcdImage:
+        required: true
+        type: string
+
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+      - name: 'Set Up Java'
+        uses: actions/setup-java@v4
+        with:
+          java-version: ${{ inputs.javaVersion }}
+          distribution: 'temurin'
+          cache: 'gradle'
+      - name: 'Build Project'
+        env:
+          ETCD_IMAGE: ${{ inputs.etcdImage }}
+        run: |
+          export TC_USER="$(id -u):$(id -g)"
+          echo "tc user -> $TC_USER"
+
+          ./gradlew test --info

.github/workflows/checks.yml

@@ -0,0 +1,37 @@
+name: Checks
+
+on:
+  workflow_call:
+
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: 'Set Up Java'
+        uses: actions/setup-java@v4
+        with:
+          java-version: 11
+          distribution: 'temurin'
+          cache: 'gradle'
+      - name: 'Run check task'
+        run: |
+          ./gradlew check -x test
+      - name: 'Run check script'
+        run: |
+          bash ./.github/workflows/scripts/precheck.sh
+        shell: bash
+
+  deps:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@v4
+      - name: 'Dependency Review'
+        uses: actions/dependency-review-action@v4

.github/workflows/scripts/precheck.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+
+failed=0
+
+# Check trailing whitespace
+files=$(find . -type f \
+    -not -path "./.git/*" \
+    -not -path "*/.gradle/*" \
+    -not -path "*/.idea/*" \
+    -not -path "*/.vscode/*" \
+    -not -path "*/build/*" \
+    -not -path "*/out/*" \
+    -not -path "*/bin/*" \
+    -not -name "*.jar" \
+    -not -name "*.java" \
+    -exec grep -E -l " +$" {} \;)
+
+count=0
+
+for file in $files; do
+    ((count++))
+    echo "$file"
+done
+
+if [ $count -ne 0 ]; then
+    failed=1
+    echo "Error: trailing whitespace(s) in the above $count file(s)"
+fi
+
+# Check newline
+files=$(find . -type f -size +0c \
+    -not -path "./.git/*" \
+    -not -path "*/.gradle/*" \
+    -not -path "*/.idea/*" \
+    -not -path "*/.vscode/*" \
+    -not -path "*/build/*" \
+    -not -path "*/out/*" \
+    -not -path "*/bin/*" \
+    -not -name "*.jar" \
+    -not -name "*.java" \
+    -exec bash -c 'if [[ $(tail -c1 "$0" | wc -l) -eq 0 ]]; then echo "$0"; fi' {} \;)
+
+count=0
+
+for file in $files; do
+    ((count++))
+    echo "$file"
+done
+
+if [ $count -ne 0 ]; then
+    failed=1
+    echo "Error: no newline in the above $count file(s)"
+fi
+
+exit $failed

.github/workflows/stale.yml

@@ -1,5 +1,5 @@
 #
-# Copyright 2016-2021 The jetcd authors
+# Copyright 2016-2023 The jetcd authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -24,18 +24,19 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/stale@v1
+    - uses: actions/stale@v9
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         days-before-stale: 60
         days-before-close: 7
+        only-labels: 'waiting-for-feedbacks'
         stale-issue-label: stale
-        exempt-issue-label: never-stale
+        exempt-issue-labels: never-stale
         stale-pr-label: stale
-        exempt-pr-label: never-stale
+        exempt-pr-labels: never-stale
         stale-issue-message: |
           This issue is stale because it has been open 60 days with no activity.
           Remove stale label or comment or this will be closed in 7 days.
         stale-pr-message: |
           This PR is stale because it has been open 60 days with no activity.
-          Remove stale label or comment or this will be closed in 7 days.
+          Remove stale label or comment or this will be closed in 7 days.

.gitignore

@@ -15,3 +15,4 @@ logs/
 .sdkmanrc
 build/
 bin/
+out/

CONTRIBUTING.md

@@ -4,7 +4,7 @@ jetcd is Apache 2.0 licensed and accepts contributions via GitHub pull requests.
 
 # Email and chat
 
-- Email: [etcd-dev](https://groups.google.com/forum/?hl=en#!forum/etcd-dev)
+- Email: [etcd-dev](https://groups.google.com/g/etcd-dev)
 - IRC: #[etcd](irc://irc.freenode.org:6667/#etcd) IRC channel on freenode.org
 
 ## Getting started
@@ -25,7 +25,7 @@ This is a rough outline of what a contributor's workflow looks like:
 - Make sure commit messages are in the proper format (see below).
 - Push changes in a topic branch to a personal fork of the repository.
 - Submit a pull request to etcd-io/jetcd.
-- The PR must receive a LGTM from at least one maintainer found in the [MAINTAINERS](https://github.com/etcd-io/etcd/blob/master/MAINTAINERS) file.
+- The PR must receive a LGTM from at least one maintainer found in the [OWNERS](https://github.com/etcd-io/jetcd/blob/main/OWNERS) file.
 
 Thanks for contributing!
 
@@ -40,7 +40,7 @@ Please follow this style to make jetcd easy to review, maintain, and develop.
 To make sure CI checks would pass please run
 
 ```bash
-./mvnw license:format
+./gradlew spotlessApply
 ```
 
 and including any changes in PR before opening it.

MAINTAINERS

@@ -1,5 +0,0 @@
-Fanmin Shi <fanmin.shi@coreos.com> (@fanminshi) pkg:*
-Luca Burgazzoli <lburgazzoli@gmail.com> (@lburgazzoli) pkg:*
-Xiang Li <xiang.li@coreos.com> (@xiang90) pkg:*
-Anthony Romano <anthony.romano@coreos.com> (@heyitsanthony) pkg:*
-

OWNERS

@@ -0,0 +1,6 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+approvers:
+  - fanminshi       # Fanmin Shi <fanmin.shi@coreos.com>
+  - lburgazzoli     # Luca Burgazzoli <lburgazzoli@gmail.com>
+  - vorburger       # Michael Vorburger <mike@vorburger.ch>

README.md

@@ -10,7 +10,7 @@ jetcd is the official java client for [etcd](https://github.com/etcd-io/etcd) v3
 
 ## Java Versions
 
-Java 8 or above is required.
+Java 11 or above is required.
 
 ## Download
 
@@ -23,7 +23,7 @@ Java 8 or above is required.
 </dependency>
 ```
 
-Development snapshots are available in [Sonatypes's snapshot repository](https://oss.sonatype.org/content/repositories/snapshots/io/etcd).
+Development snapshots are available in [Sonatypes's snapshot repository](https://oss.sonatype.org/content/repositories/snapshots/io/etcd/).
 
 ### Gradle
 
@@ -63,7 +63,7 @@ GetResponse response = getFuture.get();
 // delete the key
 kvClient.delete(key).get();
 ```
-To build one ssl secured client, refer to [secured client config](docs/sslconfig.md).
+To build one ssl secured client, refer to [secured client config](docs/SslConfig.md).
 
 For full etcd v3 API, plesase refer to the [official API documentation](https://etcd.io/docs/current/learning/api/).
 
@@ -76,11 +76,11 @@ The [jetcd-ctl](https://github.com/etcd-io/jetcd/tree/master/jetcd-ctl) is a sta
 The `io.etcd:jetcd-test` offers a convenient utility to programmatically start & stop an isolated `etcd` server.  This can be very useful e.g. for integration testing, like so:
 
 ```java
-import io.etcd.Client;
+import io.etcd.jetcd.Client;
 import io.etcd.jetcd.test.EtcdClusterExtension;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
-@RegisterExtension 
+@RegisterExtension
 public static final EtcdClusterExtension cluster = EtcdClusterExtension.builder()
         .withNodes(1)
         .build();
@@ -99,7 +99,7 @@ The current major version is zero (0.y.z). Anything may change at any time. The
 
 ## Build from source
 
-The project can be built with [Apache Maven](https://maven.apache.org/):
+The project can be built with [Gradle](https://gradle.org/):
 
 ```
 ./gradlew compileJava
@@ -111,7 +111,7 @@ The project is tested against a three node `etcd` setup started with the Launche
 
 ```sh
 $ ./gradlew test
-````
+```
 
 ### Troubleshooting
 
@@ -119,7 +119,7 @@ It recommmonds building the project before running tests so that you have artifa
 
 ## Contact
 
-* Mailing list: [etcd-dev](https://groups.google.com/forum/?hl=en#!forum/etcd-dev)
+* Mailing list: [etcd-dev](https://groups.google.com/g/etcd-dev)
 
 ## Contributing
 
@@ -128,3 +128,5 @@ See [CONTRIBUTING](https://github.com/etcd-io/jetcd/blob/master/CONTRIBUTING.md)
 ## License
 
 jetcd is under the Apache 2.0 license. See the [LICENSE](https://github.com/etcd-io/jetcd/blob/master/LICENSE) file for details.
+
+

build.gradle

@@ -63,7 +63,7 @@ subprojects {
     }
 
     compileJava {
-        options.release = 8
+        options.release = 11
     }
 
     test {
@@ -72,16 +72,29 @@ subprojects {
         maxParallelForks = Runtime.runtime.availableProcessors() ?: 1
 
         retry {
-            maxRetries = 3
+            maxRetries = 1
             maxFailures = 5
         }
     }
+    testing {
+        suites {
+            test {
+                useJUnitJupiter()
+            }
+        }
+    }
 
     testlogger {
         theme 'mocha-parallel'
         showStandardStreams false
     }
+
+    tasks.register('allDeps', DependencyReportTask)
+
+    tasks.withType(AbstractArchiveTask).configureEach {
+        preserveFileTimestamps = false
+        reproducibleFileOrder = true
+    }
 }
 
 
-

code-of-conduct.md

@@ -1,61 +1,3 @@
-## CoreOS Community Code of Conduct
+## etcd Community Code of Conduct
 
-### Contributor Code of Conduct
-
-As contributors and maintainers of this project, and in the interest of
-fostering an open and welcoming community, we pledge to respect all people who
-contribute through reporting issues, posting feature requests, updating
-documentation, submitting pull requests or patches, and other activities.
-
-We are committed to making participation in this project a harassment-free
-experience for everyone, regardless of level of experience, gender, gender
-identity and expression, sexual orientation, disability, personal appearance,
-body size, race, ethnicity, age, religion, or nationality.
-
-Examples of unacceptable behavior by participants include:
-
-* The use of sexualized language or imagery
-* Personal attacks
-* Trolling or insulting/derogatory comments
-* Public or private harassment
-* Publishing others' private information, such as physical or electronic addresses, without explicit permission
-* Other unethical or unprofessional conduct.
-
-Project maintainers have the right and responsibility to remove, edit, or
-reject comments, commits, code, wiki edits, issues, and other contributions
-that are not aligned to this Code of Conduct. By adopting this Code of Conduct,
-project maintainers commit themselves to fairly and consistently applying these
-principles to every aspect of managing this project. Project maintainers who do
-not follow or enforce the Code of Conduct may be permanently removed from the
-project team.
-
-This code of conduct applies both within project spaces and in public spaces
-when an individual is representing the project or its community.
-
-Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting a project maintainer, Brandon Philips
-<brandon.philips@coreos.com>, and/or Rithu John <rithu.john@coreos.com>.
-
-This Code of Conduct is adapted from the Contributor Covenant
-(http://contributor-covenant.org), version 1.2.0, available at
-http://contributor-covenant.org/version/1/2/0/
-
-### CoreOS Events Code of Conduct
-
-CoreOS events are working conferences intended for professional networking and
-collaboration in the CoreOS community. Attendees are expected to behave
-according to professional standards and in accordance with their employer’s
-policies on appropriate workplace behavior.
-
-While at CoreOS events or related social networking opportunities, attendees
-should not engage in discriminatory or offensive speech or actions including
-but not limited to gender, sexuality, race, age, disability, or religion.
-Speakers should be especially aware of these concerns.
-
-CoreOS does not condone any statements by speakers contrary to these standards.
-CoreOS reserves the right to deny entrance and/or eject from an event (without
-refund) any individual found to be engaging in discriminatory or offensive
-speech or actions.
-
-Please bring any concerns to the immediate attention of designated on-site
-staff, Brandon Philips <brandon.philips@coreos.com>, and/or Rithu John <rithu.john@coreos.com>.
+etcd follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md).

docs/KeyVal.adoc

@@ -26,6 +26,3 @@ for (KeyValue kv : response.getKvs()) {
     );
 }
 ----
-
-
-

docs/Lease.md

@@ -46,7 +46,7 @@ The Lease interface provides methods to grant, revoke, and keepalive leases.
 1. This function is called periodically by `keepAliveSchedule`.
 2. The lease may expire as:
      * The etcd respond overtime.
-     * The client faile to send request in time.
+     * The client fails to send request in time.
 3. It will scan the keepAlives map and find the leases that requires keepAlive requests to send based on its nextKeepAliveTime.
 4. Send request to the StreamObserver for these leases.
 
@@ -66,4 +66,4 @@ The Lease interface provides methods to grant, revoke, and keepalive leases.
 
 1. The StreamObserver is the stream etcd uses to send responses.
 2. The gRPC client calls onNext when etcd server delivers a response.
-3. The onNext function will call `processKeepAliveRespond`.
+3. The onNext function will call `processKeepAliveRespond`.

docs/RELEASE.adoc

@@ -0,0 +1,21 @@
+= Release
+
++
+[source,shell]
+----
+$ ./gradlew currentVersion
+Project version: 0.7.5-SNAPSHOT
+
+$ ./gradlew release
+
+$ git tag
+jetcd-0.7.5
+
+$ ./gradlew currentVersion
+Project version: 0.7.5
+
+$ ./gradlew publish
+published jetcd-0.7.5 release version
+
+$ ./gradlew markNextVersion -Prelease.version=0.7.6
+----

docs/SslConfig.md

@@ -3,16 +3,16 @@
 # prepare certification files
 
 If your etcd cluster is installed using [etcdadm](https://github.com/kubernetes-sigs/etcdadm), you are likely to find
-certification files in the path `/etc/etcd/pki/`: `ca.crt`, `etcdctl-etcd-client.key`, `etcdctl-etcd-client.crt`
+certification files in the path `/etc/etcd/pki/`: `ca.crt`, `etcdctl-etcd-client.key`, `etcdctl-etcd-client.crt`.
 
 If your etcd cluster is the builtin etcd in one kubernetes cluster(
 using [kubeadm](https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/setup-ha-etcd-with-kubeadm/)),
 
-you can find the same files in `/etc/kubernetes/pki/etcd/`: `ca.crt`, `healthcheck-client.crt`, `healthcheck-client.key`
+you can find the same files in `/etc/kubernetes/pki/etcd/`: `ca.crt`, `healthcheck-client.crt`, `healthcheck-client.key`.
 
 Because `SslContextBuilder` only support a PKCS#8 private key file in PEM format, convert  `etcdctl-etcd-client.key`
 to `etcdctl-etcd-client.key.pem` according
-to [netty SslContextBuilder doc](https://netty.io/wiki/sslcontextbuilder-and-private-key.html)
+to [netty SslContextBuilder doc](https://netty.io/wiki/sslcontextbuilder-and-private-key.html).
 
 # build jetcd client
 
@@ -28,9 +28,9 @@ to [netty SslContextBuilder doc](https://netty.io/wiki/sslcontextbuilder-and-pri
                 .endpoints("https://10.168.168.66:2379")
                 .sslContext(context)
                 .build();
-        
+
         client.getClusterClient().listMember().get().getMembers().forEach(member -> {
             logger.info("member: {}", member);
         });
 
-```
+```

docs/Watch.md

@@ -12,15 +12,15 @@ The Watch provide methods to watch on a key interval and cancel a watcher. If th
 
 4. Cancel watch request, the etcd client should process watch cancellation and filter all the notification after cancellation request.
 
-5. The watch client should be able to make a progress notify request that propagates the latest revision number to all watches
+5. The watch client should be able to make a progress notify request that propagates the latest revision number to all watches.
 
 # Implementation
 
-The etcd client process watch request with [watch function](#watch-function), process notification with [processEvents function](#processevents-function) , process resume with [resume function](#resume-function), process cancel with [cancelWatch function](#cancelwatch-function) and request progress with [requestProgress function](#requestProgress-function).
+The etcd client process watch request with [watch function](#watch-function), process notification with [processEvents function](#processevents-function), process resume with [resume function](#resume-function), process cancel with [cancelWatch function](#cancelwatch-function) and request progress with [requestProgress function](#requestProgress-function).
 
 ## watch function
 
-Watch watches on a key interval. 
+Watch watches on a key interval.
 
 1. Send create request to [requestStream](#requeststream-instance).
 2. If the watch is create successfully, the `onCreate` will be called and the ListenableFuture task will be completed.
@@ -116,4 +116,4 @@ Process cancel response from etcd server.
 Resume all the the watchers on new requestStream.
 
 1. Build new watch creation request for old watcher with last revision + 1.
-2. Call `watch` function with the new watch creation request.
+2. Call `watch` function with the new watch creation request.

etc/eclipse-formatter-config.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-    Copyright 2016-2021 The jetcd authors
+    Copyright 2016-2023 The jetcd authors
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
@@ -271,4 +271,3 @@
         <setting id="org.eclipse.jdt.core.formatter.enabling_tag" value="CHECKSTYLE:ON"/>
     </profile>
 </profiles>
-

etc/license.txt

@@ -10,4 +10,4 @@ Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
-limitations under the License.
+limitations under the License.

etc/pmd-ruleset.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-    Copyright 2016-2021 The jetcd authors
+    Copyright 2016-2023 The jetcd authors
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
@@ -23,6 +23,8 @@
 
     <description>PMD Rules that govern static code analysis for jetcd</description>
 
+    <exclude-pattern>.*/io/etcd/jetcd/api/.*</exclude-pattern>
+
     <rule ref="category/java/bestpractices.xml/AvoidUsingHardCodedIP"/>
     <rule ref="category/java/bestpractices.xml/UnusedFormalParameter"/>
     <rule ref="category/java/bestpractices.xml/UnusedLocalVariable"/>
@@ -42,6 +44,7 @@
     <rule ref="category/java/codestyle.xml/UselessQualifiedThis"/>
     <rule ref="category/java/codestyle.xml/ControlStatementBraces"/>
     <rule ref="category/java/codestyle.xml/UnnecessaryImport"/>
+    <rule ref="category/java/codestyle.xml/EmptyControlStatement"/>
 
     <rule ref="category/java/design.xml/FinalFieldCouldBeStatic">
         <priority>4</priority>
@@ -71,15 +74,6 @@
         </properties>
     </rule>
 
-    <rule ref="category/java/errorprone.xml/EmptyFinallyBlock"/>
-    <rule ref="category/java/errorprone.xml/EmptyIfStmt"/>
-    <rule ref="category/java/errorprone.xml/EmptyInitializer"/>
-    <rule ref="category/java/errorprone.xml/EmptyStatementBlock"/>
-    <rule ref="category/java/errorprone.xml/EmptyStatementNotInLoop"/>
-    <rule ref="category/java/errorprone.xml/EmptySwitchStatements"/>
-    <rule ref="category/java/errorprone.xml/EmptySynchronizedBlock"/>
-    <rule ref="category/java/errorprone.xml/EmptyTryBlock"/>
-    <rule ref="category/java/errorprone.xml/EmptyWhileStmt"/>
     <rule ref="category/java/errorprone.xml/JumbledIncrementer"/>
     <rule ref="category/java/errorprone.xml/MisplacedNullCheck"/>
     <rule ref="category/java/errorprone.xml/OverrideBothEqualsAndHashcode"/>
@@ -96,4 +90,4 @@
 
     <rule ref="category/java/performance.xml/BigIntegerInstantiation"/>
     <rule ref="category/java/bestpractices.xml/PrimitiveWrapperInstantiation" />
-</ruleset>
+</ruleset>

gradle.properties

@@ -1,11 +1,10 @@
 #
 # project
 #
-gitProject  = 'https://github.com/etcd-io/jetcd'
-gitURL      = 'git@github.com/etcd-io/jetcd.git'
+gitProject  = https://github.com/etcd-io/jetcd
+gitURL      = git@github.com/etcd-io/jetcd.git
 
 #
 # gradle
 #
 org.gradle.parallel = true
-

gradle/libs.versions.toml

@@ -1,46 +1,46 @@
 [versions]
-grpc = "1.45.0"
-log4j = "2.17.2"
-mockito = "4.4.0"
-slf4j = "1.7.36"
-guava = "31.1-jre"
+grpc = "1.74.0"
+log4j = "2.25.1"
+mockito = "5.18.0"
+slf4j = "2.0.17"
+guava = "33.4.8-jre"
+assertj = "3.27.3"
+junit = "5.13.4"
+testcontainers = "1.21.3"
+protoc = "3.25.1"
+failsafe = "3.3.2"
+awaitility = "4.3.0"
+commonsIo = "2.20.0"
+commonCompress = "1.28.0"
+autoService = "1.1.1"
+errorprone = "2.30.0"
+vertx = "5.0.1"
+picocli = "4.7.7"
+restAssured = "5.5.5"
 javaxAnnotation = "1.3.2"
-assertj = "3.22.0"
-junit = "5.8.2"
-testcontainers = "1.16.3"
-protoc = "3.17.2"
-failsafe = "2.4.4"
-awaitility = "4.2.0"
-commonsIo = "2.11.0"
-commonCompress = "1.21"
-autoService = "1.0.1"
-jool = "0.9.14"
-jcommander = "1.82"
-errorprone = "2.11.0"
-vertx = "4.2.6"
 
-versionsPlugin = "0.42.0"
-errorPronePlugin = "2.0.2"
-spotlessPlugin = "6.3.0"
-shadowPlugin = "7.1.2"
-testLoggerPlugin = "3.2.0"
-protobufPlugin = "0.8.18"
-nexusPublishPlugin = "1.1.0"
-axionReleasePlugin = "1.13.6"
-testRetryPlugin = "1.3.1"
+versionsPlugin = "0.52.0"
+errorPronePlugin = "4.0.1"
+spotlessPlugin = "6.25.0"
+shadowPlugin = "8.1.1"
+testLoggerPlugin = "4.0.0"
+protobufPlugin = "0.9.5"
+nexusPublishPlugin = "2.0.0"
+axionReleasePlugin = "1.18.17"
+testRetryPlugin = "1.6.2"
+
 
 [libraries]
 slf4j = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
 guava = { module = "com.google.guava:guava", version.ref = "guava" }
-javaxAnnotation = { module = "javax.annotation:javax.annotation-api", version.ref = "javaxAnnotation" }
 assertj = { module = "org.assertj:assertj-core", version.ref = "assertj" }
 junit = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit" }
 testcontainers = { module = "org.testcontainers:testcontainers", version.ref = "testcontainers" }
 protoc = { module = "com.google.protobuf:protoc", version.ref = "protoc" }
-failsafe = { module = "net.jodah:failsafe", version.ref = "failsafe" }
+failsafe = { module = "dev.failsafe:failsafe", version.ref = "failsafe" }
 awaitility = { module = "org.awaitility:awaitility", version.ref = "awaitility" }
-jcommander = { module = "com.beust:jcommander", version.ref = "jcommander"}
-jool = { module = "org.jooq:jool-java-8", version.ref = "jool"}
+picocli  = { module = "info.picocli:picocli", version.ref = "picocli"}
+restAssured = { module = "io.rest-assured:rest-assured", version.ref = "restAssured"}
 
 commonsIo = { module = "commons-io:commons-io", version.ref = "commonsIo" }
 commonsCompress = { module = "org.apache.commons:commons-compress", version.ref = "commonCompress" }
@@ -53,26 +53,32 @@ grpcNetty = { module = "io.grpc:grpc-netty", version.ref = "grpc" }
 grpcProtobuf = { module = "io.grpc:grpc-protobuf", version.ref = "grpc" }
 grpcStub = { module = "io.grpc:grpc-stub", version.ref = "grpc" }
 grpcGrpclb = { module = "io.grpc:grpc-grpclb", version.ref = "grpc" }
+grpcInprocess = { module = "io.grpc:grpc-inprocess", version.ref = "grpc" }
+grpcUtil = { module = "io.grpc:grpc-util", version.ref = "grpc" }
 
 vertxGrpc = { module = "io.vertx:vertx-grpc", version.ref = "vertx" }
 
 log4jApi = { module = "org.apache.logging.log4j:log4j-api", version.ref = "log4j" }
 log4jCore = { module = "org.apache.logging.log4j:log4j-core", version.ref = "log4j" }
-log4jSlf4j = { module = "org.apache.logging.log4j:log4j-slf4j-impl", version.ref = "log4j" }
+log4jSlf4j = { module = "org.apache.logging.log4j:log4j-slf4j2-impl", version.ref = "log4j" }
 log4j12 = { module = "org.apache.logging.log4j:log4j-1.2-api", version.ref = "log4j" }
 
 autoServiceAnnotations = { module = "com.google.auto.service:auto-service-annotations", version.ref = "autoService"}
 autoServiceProcessor = { module = "com.google.auto.service:auto-service", version.ref = "autoService"}
 
+javaxAnnotation = { module = "javax.annotation:javax.annotation-api", version.ref = "javaxAnnotation" }
 
 errorprone = { module = "com.google.errorprone:error_prone_core", version.ref = "errorprone" }
-errorproneJavac = { module = "com.google.errorprone:javac", version = "9+181-r4173-1" }
+errorproneAnnotations = { module = "com.google.errorprone:error_prone_annotations", version.ref = "errorprone" }
+errorproneJavac = { module = "com.google.errorprone:javac", version = "9+" }
 
 [bundles]
-grpc    = [ "grpcCore", "grpcNetty", "grpcProtobuf", "grpcStub", "grpcGrpclb" ]
-log4j   = [ "log4jApi", "log4jCore", "log4jSlf4j", "log4j12" ]
-mockito = [ "mockitoCore", "mockitoJunit" ]
-testing = ["junit", "assertj", "mockitoCore", "mockitoJunit"]
+grpc     = [ "grpcCore", "grpcNetty", "grpcProtobuf", "grpcStub", "grpcGrpclb", "grpcUtil"]
+grpcTest = [ "grpcInprocess"]
+log4j    = [ "log4jApi", "log4jCore", "log4jSlf4j", "log4j12" ]
+mockito  = [ "mockitoCore", "mockitoJunit" ]
+testing  = ["junit", "assertj", "mockitoCore", "mockitoJunit"]
+javax    = [ "javaxAnnotation" ]
 
 
 [plugins]

gradle/publish.gradle

@@ -20,10 +20,10 @@ apply plugin: "io.github.gradle-nexus.publish-plugin"
 
 ext {
     if (!project.hasProperty('nexusUsername')) {
-        nexusUsername = "$System.env.OSSRH_USERNAME"
+        nexusUsername = "$System.env.NEXUS_USERNAME"
     }
     if (!project.hasProperty('nexusPassword')) {
-        nexusPassword = "$System.env.OSSRH_PASSWORD"
+        nexusPassword = "$System.env.NEXUS_PASSWORD"
     }
 }
 

gradle/publishing-release-tasks.gradle

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 The jetcd authors
+ * Copyright 2016-2023 The jetcd authors
  *
  * Licensed under the Apache License, Version 2.0 (the 'License');
  * you may not use this file except in compliance with the License.
@@ -22,4 +22,4 @@ task pubblications {
             println "Publication $publication.name [$publication.groupId/$publication.artifactId/$publication.version]"
         }
     }
-}
+}

gradle/publishing-release.gradle

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 The jetcd authors
+ * Copyright 2016-2023 The jetcd authors
  *
  * Licensed under the Apache License, Version 2.0 (the 'License');
  * you may not use this file except in compliance with the License.
@@ -89,9 +89,12 @@ signing {
     sign publishing.publications."${project.name}"
 }
 
+check.dependsOn javadoc
+
 javadoc {
     if(JavaVersion.current().isJava9Compatible()) {
         options.addBooleanOption('html5', true)
     }
-}
 
+    exclude "**/io/etcd/jetcd/api/**"
+}

gradle/quality.gradle

@@ -19,6 +19,7 @@ apply plugin: "pmd"
 
 dependencies {
     errorprone(libs.errorprone)
+    errorprone(libs.errorproneAnnotations)
     errorproneJavac(libs.errorproneJavac)
 }
 
@@ -27,9 +28,10 @@ tasks.withType(JavaCompile).configureEach {
         excludedPaths = '.*/generated/.*'
         disableWarningsInGeneratedCode = true
     }
+    options.deprecation = true
 }
 
 pmd {
     consoleOutput = true
-    ruleSets = [ rootProject.file("etc/pmd-ruleset.xml") ]
+    ruleSets = [ "${project.rootDir}/etc/pmd-ruleset.xml" ]
 }

gradle/release.gradle

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 The jetcd authors
+ * Copyright 2016-2023 The jetcd authors
  *
  * Licensed under the Apache License, Version 2.0 (the 'License');
  * you may not use this file except in compliance with the License.
@@ -25,4 +25,4 @@ scmVersion {
 
 allprojects {
     project.version = scmVersion.version
-}
+}

gradle/style.gradle

@@ -24,7 +24,6 @@ spotless {
         endWithNewline()
         importOrderFile(rootProject.file('etc/eclipse.importorder'))
         eclipse().configFile(rootProject.file('etc/eclipse-formatter-config.xml'))
-        //licenseHeaderFile(rootProject.file('etc/license.txt'))
-        //licenseHeader 'Copyright $YEAR The jetcd authors'
+        targetExclude("build/generated/**/*.java")
     }
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,13 +82,11 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -114,7 +114,7 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+CLASSPATH="\\\"\\\""
 
 
 # Determine the Java command to use to start the JVM.
@@ -133,22 +133,29 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -193,18 +200,28 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
         -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
         "$@"
 
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
 # Use "xargs" to parse quoted args.
 #
 # With -n1 it outputs one arg per line, with the quotes and backslashes removed.

gradlew.bat

@@ -1,89 +1,94 @@
-@rem
-@rem Copyright 2015 the original author or authors.
-@rem
-@rem Licensed under the Apache License, Version 2.0 (the "License");
-@rem you may not use this file except in compliance with the License.
-@rem You may obtain a copy of the License at
-@rem
-@rem      https://www.apache.org/licenses/LICENSE-2.0
-@rem
-@rem Unless required by applicable law or agreed to in writing, software
-@rem distributed under the License is distributed on an "AS IS" BASIS,
-@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-@rem See the License for the specific language governing permissions and
-@rem limitations under the License.
-@rem
-
-@if "%DEBUG%" == "" @echo off
-@rem ##########################################################################
-@rem
-@rem  Gradle startup script for Windows
-@rem
-@rem ##########################################################################
-
-@rem Set local scope for the variables with windows NT shell
-if "%OS%"=="Windows_NT" setlocal
-
-set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
-set APP_BASE_NAME=%~n0
-set APP_HOME=%DIRNAME%
-
-@rem Resolve any "." and ".." in APP_HOME to make it shorter.
-for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
-
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
-
-@rem Find java.exe
-if defined JAVA_HOME goto findJavaFromJavaHome
-
-set JAVA_EXE=java.exe
-%JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto execute
-
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:findJavaFromJavaHome
-set JAVA_HOME=%JAVA_HOME:"=%
-set JAVA_EXE=%JAVA_HOME%/bin/java.exe
-
-if exist "%JAVA_EXE%" goto execute
-
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
-
-goto fail
-
-:execute
-@rem Setup the command line
-
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
-
-
-@rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
-
-:end
-@rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
-
-:fail
-rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
-rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
-
-:mainEnd
-if "%OS%"=="Windows_NT" endlocal
-
-:omega
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

jetcd-common/src/main/java/io/etcd/jetcd/common/exception/ErrorCode.java

@@ -31,12 +31,22 @@ import io.grpc.Status;
  */
 public enum ErrorCode {
 
-    CANCELLED(Status.CANCELLED), UNKNOWN(Status.UNKNOWN), INVALID_ARGUMENT(Status.INVALID_ARGUMENT),
-    DEADLINE_EXCEEDED(Status.DEADLINE_EXCEEDED), NOT_FOUND(Status.NOT_FOUND), ALREADY_EXISTS(Status.ALREADY_EXISTS),
-    PERMISSION_DENIED(Status.PERMISSION_DENIED), UNAUTHENTICATED(Status.UNAUTHENTICATED),
-    RESOURCE_EXHAUSTED(Status.RESOURCE_EXHAUSTED), FAILED_PRECONDITION(Status.FAILED_PRECONDITION), ABORTED(Status.ABORTED),
-    OUT_OF_RANGE(Status.OUT_OF_RANGE), UNIMPLEMENTED(Status.UNIMPLEMENTED), INTERNAL(Status.INTERNAL),
-    UNAVAILABLE(Status.UNAVAILABLE), DATA_LOSS(Status.DATA_LOSS),;
+    CANCELLED(Status.CANCELLED),
+    UNKNOWN(Status.UNKNOWN),
+    INVALID_ARGUMENT(Status.INVALID_ARGUMENT),
+    DEADLINE_EXCEEDED(Status.DEADLINE_EXCEEDED),
+    NOT_FOUND(Status.NOT_FOUND),
+    ALREADY_EXISTS(Status.ALREADY_EXISTS),
+    PERMISSION_DENIED(Status.PERMISSION_DENIED),
+    UNAUTHENTICATED(Status.UNAUTHENTICATED),
+    RESOURCE_EXHAUSTED(Status.RESOURCE_EXHAUSTED),
+    FAILED_PRECONDITION(Status.FAILED_PRECONDITION),
+    ABORTED(Status.ABORTED),
+    OUT_OF_RANGE(Status.OUT_OF_RANGE),
+    UNIMPLEMENTED(Status.UNIMPLEMENTED),
+    INTERNAL(Status.INTERNAL),
+    UNAVAILABLE(Status.UNAVAILABLE),
+    DATA_LOSS(Status.DATA_LOSS),;
 
     private static final Map<Integer, ErrorCode> errorByRpcCode;
 

jetcd-common/src/main/java/io/etcd/jetcd/common/exception/EtcdException.java

@@ -16,7 +16,7 @@
 
 package io.etcd.jetcd.common.exception;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import java.util.Objects;
 
 /**
  * Base exception type for all exceptions produced by the etcd service.
@@ -27,7 +27,7 @@ public class EtcdException extends RuntimeException {
 
     EtcdException(ErrorCode code, String message, Throwable cause) {
         super(message, cause);
-        this.code = checkNotNull(code);
+        this.code = Objects.requireNonNull(code, "Error code must not be null");
     }
 
     /**

jetcd-common/src/main/java/io/etcd/jetcd/common/exception/EtcdExceptionFactory.java

@@ -16,9 +16,10 @@
 
 package io.etcd.jetcd.common.exception;
 
+import java.util.Objects;
+
 import io.grpc.Status;
 
-import static com.google.common.base.Preconditions.checkNotNull;
 import static io.grpc.Status.fromThrowable;
 
 /**
@@ -65,7 +66,7 @@ public final class EtcdExceptionFactory {
     }
 
     public static EtcdException toEtcdException(Throwable cause) {
-        checkNotNull(cause, "cause can't be null");
+        Objects.requireNonNull(cause, "cause can't be null");
         if (cause instanceof EtcdException) {
             return (EtcdException) cause;
         }
@@ -74,7 +75,7 @@ public final class EtcdExceptionFactory {
     }
 
     public static EtcdException toEtcdException(Status status) {
-        checkNotNull(status, "status can't be null");
+        Objects.requireNonNull(status, "status can't be null");
         return fromStatus(status);
     }
 

jetcd-core/build.gradle

@@ -20,9 +20,10 @@ dependencies {
     api project(':jetcd-common')
 
     api libs.slf4j
+    api libs.guava
     api libs.failsafe
 
-    compileOnly libs.javaxAnnotation
+    //compileOnly libs.javaxAnnotation
     compileOnly libs.autoServiceAnnotations
 
     annotationProcessor libs.autoServiceProcessor
@@ -30,6 +31,7 @@ dependencies {
     testImplementation project(':jetcd-launcher')
     testImplementation project(':jetcd-test')
 
+    testImplementation libs.restAssured
     testImplementation libs.awaitility
     testImplementation libs.commonsIo
     testImplementation libs.bundles.testing

jetcd-core/src/main/java/io/etcd/jetcd/ByteSequence.java

@@ -17,8 +17,8 @@
 package io.etcd.jetcd;
 
 import java.nio.charset.Charset;
+import java.util.Objects;
 
-import com.google.common.base.Preconditions;
 import com.google.protobuf.ByteString;
 
 /**
@@ -32,7 +32,7 @@ public final class ByteSequence {
     private final ByteString byteString;
 
     private ByteSequence(ByteString byteString) {
-        Preconditions.checkNotNull(byteString, "byteString should not be null");
+        Objects.requireNonNull(byteString, "byteString should not be null");
         this.byteString = byteString;
         this.hashVal = byteString.hashCode();
     }
@@ -48,9 +48,7 @@ public final class ByteSequence {
         if (prefix == null) {
             return false;
         }
-        ByteString baseByteString = byteString;
-        ByteString prefixByteString = prefix.byteString;
-        return baseByteString.startsWith(prefixByteString);
+        return byteString.startsWith(prefix.byteString);
     }
 
     /**
@@ -60,7 +58,7 @@ public final class ByteSequence {
      * @return       a new {@code ByteSequence} instance
      */
     public ByteSequence concat(ByteSequence other) {
-        Preconditions.checkNotNull(other, "other byteSequence should not be null");
+        Objects.requireNonNull(other, "other byteSequence should not be null");
         return new ByteSequence(this.byteString.concat(other.byteString));
     }
 
@@ -71,7 +69,7 @@ public final class ByteSequence {
      * @return       a new {@code ByteSequence} instance
      */
     public ByteSequence concat(ByteString other) {
-        Preconditions.checkNotNull(other, "other byteSequence should not be null");
+        Objects.requireNonNull(other, "other byteSequence should not be null");
         return new ByteSequence(this.byteString.concat(other));
     }
 
@@ -157,10 +155,22 @@ public final class ByteSequence {
         return new ByteSequence(ByteString.copyFrom(bytes));
     }
 
+    /**
+     * Create new ByteSequence from a {@link ByteString}.
+     *
+     * @param  source input {@link ByteString}
+     * @return        the ByteSequence
+     */
     public static ByteSequence from(ByteString source) {
         return new ByteSequence(source);
     }
 
+    /**
+     * Create new ByteSequence from raw bytes.
+     *
+     * @param  source input bytes
+     * @return        the ByteSequence
+     */
     public static ByteSequence from(byte[] source) {
         return new ByteSequence(ByteString.copyFrom(source));
     }

jetcd-core/src/main/java/io/etcd/jetcd/Client.java

@@ -27,41 +27,57 @@ public interface Client extends AutoCloseable {
 
     /**
      * Returns the {@link Auth} client.
+     *
+     * @return the client.
      */
     Auth getAuthClient();
 
     /**
      * Returns the {@link KV} client.
+     *
+     * @return the client.
      */
     KV getKVClient();
 
     /**
      * Returns the {@link Cluster} client.
+     *
+     * @return the client.
      */
     Cluster getClusterClient();
 
     /**
      * Returns the {@link Maintenance} client.
+     *
+     * @return the client.
      */
     Maintenance getMaintenanceClient();
 
     /**
      * Returns the {@link Lease} client.
+     *
+     * @return the client.
      */
     Lease getLeaseClient();
 
     /**
      * Returns the {@link Watch} client.
+     *
+     * @return the client.
      */
     Watch getWatchClient();
 
     /**
      * Returns the {@link Lock} client.
+     *
+     * @return the client.
      */
     Lock getLockClient();
 
     /**
      * Returns the {@link Election} client.
+     *
+     * @return the client.
      */
     Election getElectionClient();
 
@@ -70,6 +86,8 @@ public interface Client extends AutoCloseable {
 
     /**
      * Returns a new {@link ClientBuilder}.
+     *
+     * @return the builder.
      */
     static ClientBuilder builder() {
         return new ClientBuilder();

jetcd-core/src/main/java/io/etcd/jetcd/ClientBuilder.java

@@ -19,16 +19,12 @@ package io.etcd.jetcd;
 import java.net.URI;
 import java.time.Duration;
 import java.time.temporal.ChronoUnit;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.ExecutorService;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import javax.net.ssl.SSLException;
 
@@ -41,13 +37,12 @@ import io.grpc.Metadata;
 import io.grpc.netty.GrpcSslContexts;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslContextBuilder;
+import io.vertx.core.Vertx;
 
-import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
-import com.google.common.collect.Streams;
 
 /**
- * ClientBuilder knows how to create an Client instance.
+ * ClientBuilder knows how to create a Client instance.
  */
 public final class ClientBuilder implements Cloneable {
 
@@ -66,6 +61,7 @@ public final class ClientBuilder implements Cloneable {
     private ByteSequence namespace = ByteSequence.EMPTY;
     private long retryDelay = 500;
     private long retryMaxDelay = 2500;
+    private int retryMaxAttempts = 2;
     private ChronoUnit retryChronoUnit = ChronoUnit.MILLIS;
     private Duration keepaliveTime = Duration.ofSeconds(30L);
     private Duration keepaliveTimeout = Duration.ofSeconds(10L);
@@ -73,6 +69,7 @@ public final class ClientBuilder implements Cloneable {
     private Duration retryMaxDuration;
     private Duration connectTimeout;
     private boolean waitForReady = true;
+    private Vertx vertx;
 
     ClientBuilder() {
     }
@@ -135,7 +132,7 @@ public final class ClientBuilder implements Cloneable {
      * @throws IllegalArgumentException if some endpoint is invalid
      */
     public ClientBuilder endpoints(Iterable<URI> endpoints) {
-        Preconditions.checkNotNull(endpoints, "endpoints can't be null");
+        Objects.requireNonNull(endpoints, "endpoints can't be null");
 
         endpoints.forEach(e -> {
             if (e.getHost() == null) {
@@ -143,8 +140,8 @@ public final class ClientBuilder implements Cloneable {
             }
         });
 
-        final String target = Streams.stream(endpoints)
-            .map(e -> e.getHost() + (e.getPort() != -1 ? (":" + e.getPort()) : ""))
+        final String target = StreamSupport.stream(endpoints.spliterator(), false)
+            .map(e -> e.getHost() + (e.getPort() != -1 ? ":" + e.getPort() : ""))
             .distinct()
             .collect(Collectors.joining(","));
 
@@ -162,6 +159,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the auth user
+     *
+     * @return the user.
      */
     public ByteSequence user() {
         return user;
@@ -175,13 +174,15 @@ public final class ClientBuilder implements Cloneable {
      * @throws NullPointerException if user is <code>null</code>
      */
     public ClientBuilder user(ByteSequence user) {
-        Preconditions.checkNotNull(user, "user can't be null");
+        Objects.requireNonNull(user, "user can't be null");
         this.user = user;
         return this;
     }
 
     /**
      * Returns the auth password
+     *
+     * @return the password.
      */
     public ByteSequence password() {
         return password;
@@ -195,13 +196,15 @@ public final class ClientBuilder implements Cloneable {
      * @throws NullPointerException if password is <code>null</code>
      */
     public ClientBuilder password(ByteSequence password) {
-        Preconditions.checkNotNull(password, "password can't be null");
+        Objects.requireNonNull(password, "password can't be null");
         this.password = password;
         return this;
     }
 
     /**
      * Returns the namespace of each key used
+     *
+     * @return the namespace.
      */
     public ByteSequence namespace() {
         return namespace;
@@ -216,13 +219,15 @@ public final class ClientBuilder implements Cloneable {
      * @throws NullPointerException if namespace is <code>null</code>
      */
     public ClientBuilder namespace(ByteSequence namespace) {
-        Preconditions.checkNotNull(namespace, "namespace can't be null");
+        Objects.requireNonNull(namespace, "namespace can't be null");
         this.namespace = namespace;
         return this;
     }
 
     /**
      * Returns the executor service
+     *
+     * @return the executor service.
      */
     public ExecutorService executorService() {
         return executorService;
@@ -236,7 +241,7 @@ public final class ClientBuilder implements Cloneable {
      * @throws NullPointerException if executorService is <code>null</code>
      */
     public ClientBuilder executorService(ExecutorService executorService) {
-        Preconditions.checkNotNull(executorService, "executorService can't be null");
+        Objects.requireNonNull(executorService, "executorService can't be null");
         this.executorService = executorService;
         return this;
     }
@@ -249,7 +254,7 @@ public final class ClientBuilder implements Cloneable {
      * @throws NullPointerException if loadBalancerPolicy is <code>null</code>
      */
     public ClientBuilder loadBalancerPolicy(String loadBalancerPolicy) {
-        Preconditions.checkNotNull(loadBalancerPolicy, "loadBalancerPolicy can't be null");
+        Objects.requireNonNull(loadBalancerPolicy, "loadBalancerPolicy can't be null");
         this.loadBalancerPolicy = loadBalancerPolicy;
         return this;
     }
@@ -265,6 +270,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the ssl context
+     *
+     * @return the ssl context.
      */
     public SslContext sslContext() {
         return sslContext;
@@ -298,6 +305,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns The authority used to authenticate connections to servers.
+     *
+     * @return the authority.
      */
     public String authority() {
         return authority;
@@ -316,6 +325,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the maximum message size allowed for a single gRPC frame.
+     *
+     * @return max inbound message size.
      */
     public Integer maxInboundMessageSize() {
         return maxInboundMessageSize;
@@ -334,6 +345,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the headers to be added to http request headers
+     *
+     * @return headers.
      */
     public Map<Metadata.Key<?>, Object> headers() {
         return headers == null ? Collections.emptyMap() : Collections.unmodifiableMap(headers);
@@ -370,6 +383,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the headers to be added to auth request headers
+     *
+     * @return auth headers.
      */
     public Map<Metadata.Key<?>, Object> authHeaders() {
         return authHeaders == null ? Collections.emptyMap() : Collections.unmodifiableMap(authHeaders);
@@ -406,6 +421,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the interceptors
+     *
+     * @return the interceptors.
      */
     public List<ClientInterceptor> interceptors() {
         return interceptors;
@@ -443,6 +460,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the auth interceptors
+     *
+     * @return the interceptors.
      */
     public List<ClientInterceptor> authInterceptors() {
         return authInterceptors;
@@ -480,6 +499,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns The delay between retries.
+     *
+     * @return the retry delay.
      */
     public long retryDelay() {
         return retryDelay;
@@ -498,6 +519,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the max backing off delay between retries
+     *
+     * @return max retry delay.
      */
     public long retryMaxDelay() {
         return retryMaxDelay;
@@ -514,6 +537,31 @@ public final class ClientBuilder implements Cloneable {
         return this;
     }
 
+    /**
+     * Returns the max number of retry attempts
+     *
+     * @return max retry attempts.
+     */
+    public int retryMaxAttempts() {
+        return retryMaxAttempts;
+    }
+
+    /**
+     * Set the max number of retry attempts
+     *
+     * @param  retryMaxAttempts The max retry attempts.
+     * @return                  this builder
+     */
+    public ClientBuilder retryMaxAttempts(int retryMaxAttempts) {
+        this.retryMaxAttempts = retryMaxAttempts;
+        return this;
+    }
+
+    /**
+     * Returns the keep alive time.
+     *
+     * @return keep alive time.
+     */
     public Duration keepaliveTime() {
         return keepaliveTime;
     }
@@ -532,6 +580,11 @@ public final class ClientBuilder implements Cloneable {
         return this;
     }
 
+    /**
+     * Returns the keep alive time out.
+     *
+     * @return keep alive time out.
+     */
     public Duration keepaliveTimeout() {
         return keepaliveTimeout;
     }
@@ -564,6 +617,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns he retries period unit.
+     *
+     * @return the chrono unit.
      */
     public ChronoUnit retryChronoUnit() {
         return retryChronoUnit;
@@ -582,6 +637,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the retries max duration.
+     *
+     * @return retry max duration.
      */
     public Duration retryMaxDuration() {
         return retryMaxDuration;
@@ -589,6 +646,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns the connect timeout.
+     *
+     * @return connect timeout.
      */
     public Duration connectTimeout() {
         return connectTimeout;
@@ -650,6 +709,30 @@ public final class ClientBuilder implements Cloneable {
         return this;
     }
 
+    /**
+     * Gets the Vertx instance.
+     *
+     * @return the vertx instance.
+     */
+    public Vertx vertx() {
+        return vertx;
+    }
+
+    /**
+     * configure Vertx instance.
+     *
+     * @param  vertx                    Vertx instance to use.
+     * @return                          this builder to train
+     * @throws IllegalArgumentException if vertx is null
+     */
+    public ClientBuilder vertx(Vertx vertx) {
+        Preconditions.checkArgument(vertx != null, "vertx can't be null");
+
+        this.vertx = vertx;
+
+        return this;
+    }
+
     /**
      * build a new Client.
      *
@@ -664,6 +747,8 @@ public final class ClientBuilder implements Cloneable {
 
     /**
      * Returns a copy of this builder
+     *
+     * @return a copy of the builder.
      */
     public ClientBuilder copy() {
         try {

jetcd-core/src/main/java/io/etcd/jetcd/Cluster.java

@@ -39,13 +39,22 @@ public interface Cluster extends CloseableClient {
     CompletableFuture<MemberListResponse> listMember();
 
     /**
-     * add a new member into the cluster.
+     * add a non-learner new member into the cluster.
      *
      * @param  peerAddrs the peer addresses of the new member
      * @return           the response
      */
     CompletableFuture<MemberAddResponse> addMember(List<URI> peerAddrs);
 
+    /**
+     * add a new member into the cluster.
+     *
+     * @param  peerAddrs the peer addresses of the new member
+     * @param  isLearner whether the member is raft learner
+     * @return           the response
+     */
+    CompletableFuture<MemberAddResponse> addMember(List<URI> peerAddrs, boolean isLearner);
+
     /**
      * removes an existing member from the cluster.
      *

jetcd-core/src/main/java/io/etcd/jetcd/Constants.java

@@ -22,11 +22,11 @@ import io.grpc.Metadata;
  * Constants of Etcd.
  */
 public class Constants {
-
-    public static final String TOKEN = "token";
     public static final ByteSequence NULL_KEY = ByteSequence.from(new byte[] { '\0' });
 
-    public static final Metadata.Key<String> REQUIRE_LEADER_KEY = Metadata.Key.of("hasleader",
+    public static final Metadata.Key<String> REQUIRE_LEADER_KEY = Metadata.Key.of(
+        "hasleader",
         Metadata.ASCII_STRING_MARSHALLER);
+
     public static final String REQUIRE_LEADER_VALUE = "true";
 }

jetcd-core/src/main/java/io/etcd/jetcd/KV.java

@@ -26,6 +26,7 @@ import io.etcd.jetcd.options.CompactOption;
 import io.etcd.jetcd.options.DeleteOption;
 import io.etcd.jetcd.options.GetOption;
 import io.etcd.jetcd.options.PutOption;
+import io.etcd.jetcd.options.TxnOption;
 import io.etcd.jetcd.support.CloseableClient;
 
 /**
@@ -115,4 +116,12 @@ public interface KV extends CloseableClient {
      * @return a Txn
      */
     Txn txn();
+
+    /**
+     * creates a transaction.
+     *
+     * @param  option TxnOption
+     * @return        a Txn
+     */
+    Txn txn(TxnOption option);
 }

jetcd-core/src/main/java/io/etcd/jetcd/KeyValue.java

@@ -29,13 +29,18 @@ public class KeyValue {
 
     public KeyValue(io.etcd.jetcd.api.KeyValue kv, ByteSequence namespace) {
         this.kv = kv;
-        this.unprefixedKey = ByteSequence
-            .from(kv.getKey().isEmpty() ? kv.getKey() : Util.unprefixNamespace(kv.getKey(), namespace));
         this.value = ByteSequence.from(kv.getValue());
+
+        this.unprefixedKey = ByteSequence.from(
+            kv.getKey().isEmpty()
+                ? kv.getKey()
+                : Util.unprefixNamespace(kv.getKey(), namespace));
     }
 
     /**
      * Returns the key
+     *
+     * @return the key.
      */
     public ByteSequence getKey() {
         return unprefixedKey;
@@ -43,6 +48,8 @@ public class KeyValue {
 
     /**
      * Returns the value
+     *
+     * @return the value.
      */
     public ByteSequence getValue() {
         return value;
@@ -50,6 +57,8 @@ public class KeyValue {
 
     /**
      * Returns the create revision.
+     *
+     * @return the create revision.
      */
     public long getCreateRevision() {
         return kv.getCreateRevision();
@@ -57,6 +66,8 @@ public class KeyValue {
 
     /**
      * Returns the mod revision.
+     *
+     * @return the mod revision.
      */
     public long getModRevision() {
         return kv.getModRevision();
@@ -64,6 +75,8 @@ public class KeyValue {
 
     /**
      * Returns the version.
+     *
+     * @return the version.
      */
     public long getVersion() {
         return kv.getVersion();
@@ -71,6 +84,8 @@ public class KeyValue {
 
     /**
      * Returns the lease.
+     *
+     * @return the lease.
      */
     public long getLease() {
         return kv.getLease();

jetcd-core/src/main/java/io/etcd/jetcd/Maintenance.java

@@ -17,16 +17,9 @@
 package io.etcd.jetcd;
 
 import java.io.OutputStream;
-import java.net.URI;
 import java.util.concurrent.CompletableFuture;
 
-import io.etcd.jetcd.maintenance.AlarmMember;
-import io.etcd.jetcd.maintenance.AlarmResponse;
-import io.etcd.jetcd.maintenance.DefragmentResponse;
-import io.etcd.jetcd.maintenance.HashKVResponse;
-import io.etcd.jetcd.maintenance.MoveLeaderResponse;
-import io.etcd.jetcd.maintenance.SnapshotResponse;
-import io.etcd.jetcd.maintenance.StatusResponse;
+import io.etcd.jetcd.maintenance.*;
 import io.etcd.jetcd.support.CloseableClient;
 import io.grpc.stub.StreamObserver;
 
@@ -68,16 +61,6 @@ public interface Maintenance extends CloseableClient {
      */
     CompletableFuture<AlarmResponse> alarmDisarm(AlarmMember member);
 
-    /**
-     * Defragment one member of the cluster by its endpoint.
-     *
-     * @param      endpoint the etcd server endpoint.
-     * @return              the response result
-     * @deprecated          use {@link #defragmentMember(String)}
-     */
-    @Deprecated
-    CompletableFuture<DefragmentResponse> defragmentMember(URI endpoint);
-
     /**
      * Defragment one member of the cluster by its endpoint.
      *
@@ -100,16 +83,6 @@ public interface Maintenance extends CloseableClient {
      */
     CompletableFuture<DefragmentResponse> defragmentMember(String target);
 
-    /**
-     * get the status of a member by its endpoint.
-     *
-     * @param      endpoint the etcd server endpoint.
-     * @return              the response result
-     * @deprecated          use {@link #statusMember(String)}
-     */
-    @Deprecated
-    CompletableFuture<StatusResponse> statusMember(URI endpoint);
-
     /**
      * get the status of a member by its endpoint.
      *
@@ -118,17 +91,6 @@ public interface Maintenance extends CloseableClient {
      */
     CompletableFuture<StatusResponse> statusMember(String target);
 
-    /**
-     * returns a hash of the KV state at the time of the RPC.
-     *
-     * @param      endpoint the etcd server endpoint.
-     * @param      rev      the revision
-     * @return              the response result
-     * @deprecated          use {@link #hashKV(String, long)}
-     */
-    @Deprecated
-    CompletableFuture<HashKVResponse> hashKV(URI endpoint, long rev);
-
     /**
      * returns a hash of the KV state at the time of the RPC.
      * If revision is zero, the hash is computed on all keys. If the revision

jetcd-core/src/main/java/io/etcd/jetcd/Preconditions.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016-2023 The jetcd authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.etcd.jetcd;
+
+public class Preconditions {
+
+    public static void checkArgument(boolean expression, String errorMessage) {
+        if (!expression) {
+            throw new IllegalArgumentException(errorMessage);
+        }
+    }
+
+    public static void checkState(boolean expression, String errorMessage) {
+        if (!expression) {
+            throw new IllegalStateException(errorMessage);
+        }
+    }
+}

jetcd-core/src/main/java/io/etcd/jetcd/Response.java

@@ -23,6 +23,8 @@ public interface Response {
 
     /**
      * Returns the response header
+     *
+     * @return the header.
      */
     Header getHeader();
 
@@ -30,21 +32,29 @@ public interface Response {
 
         /**
          * Returns the cluster id
+         *
+         * @return the cluster id.
          */
         long getClusterId();
 
         /**
          * Returns the member id
+         *
+         * @return the member id.
          */
         long getMemberId();
 
         /**
          * Returns the revision id
+         *
+         * @return the revision.
          */
         long getRevision();
 
         /**
          * Returns the raft term
+         *
+         * @return theraft term.
          */
         long getRaftTerm();
     }

jetcd-core/src/main/java/io/etcd/jetcd/Txn.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 The jetcd authors
+ * Copyright 2016-2023 The jetcd authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,20 +25,19 @@ import io.etcd.jetcd.op.Op;
 /**
  * Txn is the interface that wraps mini-transactions.
  *
- * <h3>Usage examples</h3>
+ * <h2>Usage examples</h2>
  *
  * <pre>
  * {@code
  * txn.If(
- *    new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE)),
- *    new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(2))
- * ).Then(
- *    Op.put(KEY2, VALUE2, PutOption.DEFAULT),
- *    Op.put(KEY3, VALUE3, PutOption.DEFAULT)
- * ).Else(
- *    Op.put(KEY4, VALUE4, PutOption.DEFAULT),
- *    Op.put(KEY4, VALUE4, PutOption.DEFAULT)
- * ).commit();
+ *     new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE)),
+ *     new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(2))).Then(
+ *         Op.put(KEY2, VALUE2, PutOption.DEFAULT),
+ *         Op.put(KEY3, VALUE3, PutOption.DEFAULT))
+ *     .Else(
+ *         Op.put(KEY4, VALUE4, PutOption.DEFAULT),
+ *         Op.put(KEY4, VALUE4, PutOption.DEFAULT))
+ *     .commit();
  * }
  * </pre>
  *
@@ -48,18 +47,17 @@ import io.etcd.jetcd.op.Op;
  * <pre>
  * {@code
  * txn.If(
- *    new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE))
- * ).If(
- *    new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(VERSION))
- * ).Then(
- *    Op.put(KEY2, VALUE2, PutOption.DEFAULT)
- * ).Then(
- *    Op.put(KEY3, VALUE3, PutOption.DEFAULT)
- * ).Else(
- *    Op.put(KEY4, VALUE4, PutOption.DEFAULT)
- * ).Else(
- *    Op.put(KEY4, VALUE4, PutOption.DEFAULT)
- * ).commit();
+ *     new Cmp(KEY, Cmp.Op.GREATER, CmpTarget.value(VALUE))).If(
+ *         new Cmp(KEY, cmp.Op.EQUAL, CmpTarget.version(VERSION)))
+ *     .Then(
+ *         Op.put(KEY2, VALUE2, PutOption.DEFAULT))
+ *     .Then(
+ *         Op.put(KEY3, VALUE3, PutOption.DEFAULT))
+ *     .Else(
+ *         Op.put(KEY4, VALUE4, PutOption.DEFAULT))
+ *     .Else(
+ *         Op.put(KEY4, VALUE4, PutOption.DEFAULT))
+ *     .commit();
  * }
  * </pre>
  */

jetcd-core/src/main/java/io/etcd/jetcd/Watch.java

@@ -226,6 +226,11 @@ public interface Watch extends CloseableClient {
         @Override
         void close();
 
+        /**
+         * Returns if watcher is already closed
+         */
+        boolean isClosed();
+
         /**
          * Requests the latest revision processed and propagates it to listeners
          */

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthRoleListResponse.java

@@ -33,6 +33,8 @@ public class AuthRoleListResponse extends AbstractResponse<io.etcd.jetcd.api.Aut
 
     /**
      * Returns a list of roles.
+     *
+     * @return the roles.
      */
     public List<String> getRoles() {
         return getResponse().getRolesList();

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthRoleRevokePermissionResponse.java

@@ -16,14 +16,10 @@
 
 package io.etcd.jetcd.auth;
 
-import io.etcd.jetcd.Auth;
-import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * AuthRoleRevokePermissionResponse returned by
- * {@link Auth#roleRevokePermission(ByteSequence.ByteSequence,
- * ByteSequence.ByteSequence, ByteSequence.ByteSequence)} contains a header.
+ * AuthRoleRevokePermissionResponse
  */
 public class AuthRoleRevokePermissionResponse extends AbstractResponse<io.etcd.jetcd.api.AuthRoleRevokePermissionResponse> {
 

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthUserChangePasswordResponse.java

@@ -16,14 +16,10 @@
 
 package io.etcd.jetcd.auth;
 
-import io.etcd.jetcd.Auth;
-import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * AuthUserChangePasswordResponse returned by
- * {@link Auth#userChangePassword(ByteSequence.ByteSequence,
- * ByteSequence.ByteSequence)} contains a header.
+ * AuthUserChangePasswordResponse
  */
 public class AuthUserChangePasswordResponse extends AbstractResponse<io.etcd.jetcd.api.AuthUserChangePasswordResponse> {
 

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthUserGetResponse.java

@@ -34,6 +34,8 @@ public class AuthUserGetResponse extends AbstractResponse<io.etcd.jetcd.api.Auth
 
     /**
      * Returns a list of roles.
+     *
+     * @return the roles.
      */
     public List<String> getRoles() {
         return getResponse().getRolesList();

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthUserGrantRoleResponse.java

@@ -16,14 +16,10 @@
 
 package io.etcd.jetcd.auth;
 
-import io.etcd.jetcd.Auth;
-import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * AuthUserGrantRoleResponse returned by
- * {@link Auth#userGrantRole(ByteSequence.ByteSequence,
- * ByteSequence.ByteSequence)} contains a header.
+ * AuthUserGrantRoleResponse
  */
 public class AuthUserGrantRoleResponse extends AbstractResponse<io.etcd.jetcd.api.AuthUserGrantRoleResponse> {
 

jetcd-core/src/main/java/io/etcd/jetcd/auth/AuthUserListResponse.java

@@ -33,6 +33,8 @@ public class AuthUserListResponse extends AbstractResponse<io.etcd.jetcd.api.Aut
 
     /**
      * Returns a list of users.
+     *
+     * @return the users.
      */
     public List<String> getUsers() {
         return getResponse().getUsersList();

jetcd-core/src/main/java/io/etcd/jetcd/auth/Permission.java

@@ -39,6 +39,8 @@ public class Permission {
 
     /**
      * Returns the type of Permission: READ, WRITE, READWRITE, or UNRECOGNIZED.
+     *
+     * @return the permission type.
      */
     public Type getPermType() {
         return permType;

jetcd-core/src/main/java/io/etcd/jetcd/cluster/Member.java

@@ -31,6 +31,8 @@ public class Member {
 
     /**
      * Returns the member ID for this member.
+     *
+     * @return the id.
      */
     public long getId() {
         return member.getID();
@@ -38,6 +40,8 @@ public class Member {
 
     /**
      * Returns the human-readable name of the member, ff the member is not started, the name will be an empty string.
+     *
+     * @return the name.
      */
     public String getName() {
         return member.getName();
@@ -45,6 +49,8 @@ public class Member {
 
     /**
      * Returns the list of URLs the member exposes to the cluster for communication.
+     *
+     * @return the peer url
      */
     public List<URI> getPeerURIs() {
         return Util.toURIs(member.getPeerURLsList());
@@ -53,8 +59,19 @@ public class Member {
     /**
      * Returns list of URLs the member exposes to clients for communication, if the member is not started, clientURLs will
      * be empty.
+     *
+     * @return the client URIs.
      */
     public List<URI> getClientURIs() {
         return Util.toURIs(member.getClientURLsList());
     }
+
+    /**
+     * Returns if the member is raft learner
+     *
+     * @return if the member is raft learner
+     */
+    public boolean isLearner() {
+        return member.getIsLearner();
+    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/cluster/MemberAddResponse.java

@@ -22,7 +22,7 @@ import io.etcd.jetcd.Cluster;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * MemberAddResponse returned by {@link Cluster#addMember(List)}
+ * MemberAddResponse returned by {@link Cluster#addMember(List, boolean)}
  * contains a header, added member, and list of members after adding the new member.
  */
 public class MemberAddResponse extends AbstractResponse<io.etcd.jetcd.api.MemberAddResponse> {

jetcd-core/src/main/java/io/etcd/jetcd/cluster/Util.java

@@ -22,7 +22,9 @@ import java.util.stream.Collectors;
 /**
  * Util class for Cluster models.
  */
-public class Util {
+final class Util {
+    private Util() {
+    }
 
     /**
      * Converts a list of API member to a List of client side member.

jetcd-core/src/main/java/io/etcd/jetcd/election/CampaignResponse.java

@@ -34,6 +34,8 @@ public class CampaignResponse extends AbstractResponse<io.etcd.jetcd.api.Campaig
 
     /**
      * Returns the resources used for holding leadership of the election.
+     *
+     * @return the leader.
      */
     public LeaderKey getLeader() {
         return leaderKey;

jetcd-core/src/main/java/io/etcd/jetcd/election/LeaderKey.java

@@ -32,7 +32,9 @@ public class LeaderKey {
     }
 
     /**
-     * Returns the election identifier that corresponds to the leadership key. *
+     * Returns the election identifier that corresponds to the leadership key.
+     *
+     * @return the name.
      */
     public ByteSequence getName() {
         return name;
@@ -41,6 +43,8 @@ public class LeaderKey {
     /**
      * Returns the opaque key representing the ownership of the election. If the key
      * is deleted, then leadership is lost.
+     *
+     * @return the key.
      */
     public ByteSequence getKey() {
         return key;
@@ -50,6 +54,8 @@ public class LeaderKey {
      * Returns the creation revision of the key. It can be used to test for ownership
      * of an election during transactions by testing the key's creation revision
      * matches rev.
+     *
+     * @return the revision.
      */
     public long getRevision() {
         return revision;
@@ -57,6 +63,8 @@ public class LeaderKey {
 
     /**
      * Returns the lease ID of the election leader.
+     *
+     * @return the lese id.
      */
     public long getLease() {
         return lease;

jetcd-core/src/main/java/io/etcd/jetcd/election/LeaderResponse.java

@@ -30,6 +30,8 @@ public class LeaderResponse extends AbstractResponse<io.etcd.jetcd.api.LeaderRes
 
     /**
      * Returns the key-value pair representing the latest leader update.
+     *
+     * @return the kv.
      */
     public KeyValue getKv() {
         return kv;

jetcd-core/src/main/java/io/etcd/jetcd/election/NoLeaderException.java

@@ -20,5 +20,4 @@ package io.etcd.jetcd.election;
  * Signals that leader for given election does not exist.
  */
 public class NoLeaderException extends RuntimeException {
-    public static final NoLeaderException INSTANCE = new NoLeaderException();
 }

jetcd-core/src/main/java/io/etcd/jetcd/election/NotLeaderException.java

@@ -20,5 +20,4 @@ package io.etcd.jetcd.election;
  * Signals that candidate is not a leader at the moment.
  */
 public class NotLeaderException extends RuntimeException {
-    public static final NotLeaderException INSTANCE = new NotLeaderException();
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/AuthCredential.java

@@ -31,7 +31,7 @@ import io.grpc.stub.MetadataUtils;
 
 import com.google.protobuf.ByteString;
 
-import static com.google.common.base.Preconditions.checkArgument;
+import static io.etcd.jetcd.Preconditions.checkArgument;
 
 /**
  * AuthTokenInterceptor fills header with Auth token of any rpc calls and
@@ -58,14 +58,11 @@ class AuthCredential extends CallCredentials {
         }
     }
 
-    @Override
-    public void thisUsesUnstableApi() {
-    }
-
     public void refresh() {
         meta = null;
     }
 
+    @SuppressWarnings("rawtypes")
     private void authenticate(MetadataApplier applier) {
         checkArgument(!manager.builder().user().isEmpty(), "username can not be empty.");
         checkArgument(!manager.builder().password().isEmpty(), "password can not be empty.");

jetcd-core/src/main/java/io/etcd/jetcd/impl/AuthImpl.java

@@ -55,7 +55,7 @@ import io.etcd.jetcd.auth.Permission;
 
 import com.google.protobuf.ByteString;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 /**
  * Implementation of etcd auth client.
@@ -88,8 +88,8 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserAddResponse> userAdd(ByteSequence user, ByteSequence password) {
-        checkNotNull(user, "user can't be null");
-        checkNotNull(password, "password can't be null");
+        requireNonNull(user, "user can't be null");
+        requireNonNull(password, "password can't be null");
 
         AuthUserAddRequest addRequest = AuthUserAddRequest.newBuilder()
             .setNameBytes(ByteString.copyFrom(user.getBytes()))
@@ -103,7 +103,7 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserDeleteResponse> userDelete(ByteSequence user) {
-        checkNotNull(user, "user can't be null");
+        requireNonNull(user, "user can't be null");
 
         AuthUserDeleteRequest deleteRequest = AuthUserDeleteRequest.newBuilder()
             .setNameBytes(ByteString.copyFrom(user.getBytes()))
@@ -116,8 +116,8 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserChangePasswordResponse> userChangePassword(ByteSequence user, ByteSequence password) {
-        checkNotNull(user, "user can't be null");
-        checkNotNull(password, "password can't be null");
+        requireNonNull(user, "user can't be null");
+        requireNonNull(password, "password can't be null");
 
         AuthUserChangePasswordRequest changePasswordRequest = AuthUserChangePasswordRequest.newBuilder()
             .setNameBytes(ByteString.copyFrom(user.getBytes()))
@@ -131,7 +131,7 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserGetResponse> userGet(ByteSequence user) {
-        checkNotNull(user, "user can't be null");
+        requireNonNull(user, "user can't be null");
 
         AuthUserGetRequest userGetRequest = AuthUserGetRequest.newBuilder()
             .setNameBytes(ByteString.copyFrom(user.getBytes()))
@@ -153,8 +153,8 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserGrantRoleResponse> userGrantRole(ByteSequence user, ByteSequence role) {
-        checkNotNull(user, "user can't be null");
-        checkNotNull(role, "key can't be null");
+        requireNonNull(user, "user can't be null");
+        requireNonNull(role, "key can't be null");
 
         AuthUserGrantRoleRequest userGrantRoleRequest = AuthUserGrantRoleRequest.newBuilder()
             .setUserBytes(ByteString.copyFrom(user.getBytes()))
@@ -168,8 +168,8 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthUserRevokeRoleResponse> userRevokeRole(ByteSequence user, ByteSequence role) {
-        checkNotNull(user, "user can't be null");
-        checkNotNull(role, "key can't be null");
+        requireNonNull(user, "user can't be null");
+        requireNonNull(role, "key can't be null");
 
         AuthUserRevokeRoleRequest userRevokeRoleRequest = AuthUserRevokeRoleRequest.newBuilder()
             .setNameBytes(ByteString.copyFrom(user.getBytes()))
@@ -183,7 +183,7 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthRoleAddResponse> roleAdd(ByteSequence user) {
-        checkNotNull(user, "user can't be null");
+        requireNonNull(user, "user can't be null");
 
         AuthRoleAddRequest roleAddRequest = AuthRoleAddRequest.newBuilder().setNameBytes(ByteString.copyFrom(user.getBytes()))
             .build();
@@ -196,10 +196,10 @@ final class AuthImpl extends Impl implements Auth {
     @Override
     public CompletableFuture<AuthRoleGrantPermissionResponse> roleGrantPermission(ByteSequence role, ByteSequence key,
         ByteSequence rangeEnd, Permission.Type permType) {
-        checkNotNull(role, "role can't be null");
-        checkNotNull(key, "key can't be null");
-        checkNotNull(rangeEnd, "rangeEnd can't be null");
-        checkNotNull(permType, "permType can't be null");
+        requireNonNull(role, "role can't be null");
+        requireNonNull(key, "key can't be null");
+        requireNonNull(rangeEnd, "rangeEnd can't be null");
+        requireNonNull(permType, "permType can't be null");
 
         io.etcd.jetcd.api.Permission.Type type;
         switch (permType) {
@@ -235,7 +235,7 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthRoleGetResponse> roleGet(ByteSequence role) {
-        checkNotNull(role, "role can't be null");
+        requireNonNull(role, "role can't be null");
 
         AuthRoleGetRequest roleGetRequest = AuthRoleGetRequest.newBuilder()
             .setRoleBytes(ByteString.copyFrom(role.getBytes()))
@@ -258,14 +258,14 @@ final class AuthImpl extends Impl implements Auth {
     @Override
     public CompletableFuture<AuthRoleRevokePermissionResponse> roleRevokePermission(ByteSequence role, ByteSequence key,
         ByteSequence rangeEnd) {
-        checkNotNull(role, "role can't be null");
-        checkNotNull(key, "key can't be null");
-        checkNotNull(rangeEnd, "rangeEnd can't be null");
+        requireNonNull(role, "role can't be null");
+        requireNonNull(key, "key can't be null");
+        requireNonNull(rangeEnd, "rangeEnd can't be null");
 
         AuthRoleRevokePermissionRequest roleRevokePermissionRequest = AuthRoleRevokePermissionRequest.newBuilder()
             .setRoleBytes(ByteString.copyFrom(role.getBytes()))
-            .setKeyBytes(ByteString.copyFrom(key.getBytes()))
-            .setRangeEndBytes(ByteString.copyFrom(rangeEnd.getBytes()))
+            .setKey(ByteString.copyFrom(key.getBytes()))
+            .setRangeEnd(ByteString.copyFrom(rangeEnd.getBytes()))
             .build();
 
         return completable(
@@ -275,7 +275,7 @@ final class AuthImpl extends Impl implements Auth {
 
     @Override
     public CompletableFuture<AuthRoleDeleteResponse> roleDelete(ByteSequence role) {
-        checkNotNull(role, "role can't be null");
+        requireNonNull(role, "role can't be null");
         AuthRoleDeleteRequest roleDeleteRequest = AuthRoleDeleteRequest.newBuilder()
             .setRoleBytes(ByteString.copyFrom(role.getBytes()))
             .build();

jetcd-core/src/main/java/io/etcd/jetcd/impl/ClientConnectionManager.java

@@ -16,50 +16,33 @@
 
 package io.etcd.jetcd.impl;
 
-import java.util.concurrent.Callable;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
-import java.util.function.Predicate;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.ClientBuilder;
-import io.etcd.jetcd.support.Errors;
-import io.grpc.CallOptions;
-import io.grpc.Channel;
-import io.grpc.ClientCall;
-import io.grpc.ClientInterceptor;
+import io.etcd.jetcd.support.Util;
+import io.grpc.*;
 import io.grpc.ForwardingClientCall.SimpleForwardingClientCall;
-import io.grpc.ManagedChannel;
-import io.grpc.ManagedChannelBuilder;
-import io.grpc.Metadata;
-import io.grpc.MethodDescriptor;
 import io.grpc.netty.NegotiationType;
 import io.grpc.stub.AbstractStub;
 import io.netty.channel.ChannelOption;
 import io.vertx.core.Vertx;
+import io.vertx.core.VertxOptions;
 import io.vertx.grpc.VertxChannelBuilder;
 
-import com.google.common.util.concurrent.ListenableFuture;
-
-import net.jodah.failsafe.Failsafe;
-import net.jodah.failsafe.RetryPolicy;
-
 import static io.etcd.jetcd.common.exception.EtcdExceptionFactory.toEtcdException;
 
 final class ClientConnectionManager {
-    private static final Logger LOGGER = LoggerFactory.getLogger(ClientConnectionManager.class);
-
     private final Object lock;
     private final ClientBuilder builder;
     private final ExecutorService executorService;
     private final AuthCredential credential;
+    private volatile Vertx vertx;
     private volatile ManagedChannel managedChannel;
 
     ClientConnectionManager(ClientBuilder builder) {
@@ -73,10 +56,15 @@ final class ClientConnectionManager {
         this.credential = new AuthCredential(this);
 
         if (builder.executorService() == null) {
-            this.executorService = Executors.newCachedThreadPool();
+            // default to daemon
+            this.executorService = Executors.newCachedThreadPool(Util.createThreadFactory("jetcd-", true));
         } else {
             this.executorService = builder.executorService();
         }
+
+        if (builder.vertx() != null) {
+            this.vertx = builder.vertx();
+        }
     }
 
     ManagedChannel getChannel() {
@@ -135,6 +123,9 @@ final class ClientConnectionManager {
             if (managedChannel != null) {
                 managedChannel.shutdownNow();
             }
+            if (vertx != null) {
+                vertx.close();
+            }
         }
 
         if (builder.executorService() == null) {
@@ -168,8 +159,7 @@ final class ClientConnectionManager {
             throw new IllegalArgumentException("At least one endpoint should be provided");
         }
 
-        final Vertx vertx = Vertx.vertx();
-        final VertxChannelBuilder channelBuilder = VertxChannelBuilder.forTarget(vertx, target);
+        final VertxChannelBuilder channelBuilder = VertxChannelBuilder.forTarget(vertx(), target);
 
         if (builder.authority() != null) {
             channelBuilder.overrideAuthority(builder.authority());
@@ -201,7 +191,7 @@ final class ClientConnectionManager {
         if (builder.loadBalancerPolicy() != null) {
             channelBuilder.defaultLoadBalancingPolicy(builder.loadBalancerPolicy());
         } else {
-            channelBuilder.defaultLoadBalancingPolicy("pick_first");
+            channelBuilder.defaultLoadBalancingPolicy("round_robin");
         }
 
         if (builder.headers() != null) {
@@ -230,48 +220,15 @@ final class ClientConnectionManager {
         return channelBuilder;
     }
 
-    /**
-     * execute the task and retry it in case of failure.
-     *
-     * @param  task          a function that returns a new SourceFuture.
-     * @param  resultConvert a function that converts Type S to Type T.
-     * @param  doRetry       a function that determines the retry condition base on SourceFuture error.
-     * @param  <S>           Source type
-     * @param  <T>           Converted Type.
-     * @return               a CompletableFuture with type T.
-     */
-    @SuppressWarnings("FutureReturnValueIgnored")
-    public <S, T> CompletableFuture<T> execute(
-        Callable<ListenableFuture<S>> task,
-        Function<S, T> resultConvert,
-        Predicate<Throwable> doRetry) {
-
-        RetryPolicy<CompletableFuture<S>> retryPolicy = new RetryPolicy<CompletableFuture<S>>().handleIf(doRetry)
-            .onRetriesExceeded(e -> LOGGER.warn("maximum number of auto retries reached"))
-            .withBackoff(builder.retryDelay(), builder.retryMaxDelay(), builder.retryChronoUnit());
-
-        if (builder.retryMaxDuration() != null) {
-            retryPolicy = retryPolicy.withMaxDuration(builder.retryMaxDuration());
+    Vertx vertx() {
+        if (this.vertx == null) {
+            synchronized (this.lock) {
+                if (this.vertx == null) {
+                    this.vertx = Vertx.vertx(new VertxOptions().setUseDaemonThread(true));
+                }
+            }
         }
 
-        return Failsafe.with(retryPolicy).with(executorService)
-            .getAsyncExecution(execution -> {
-                CompletableFuture<S> wrappedFuture = new CompletableFuture<>();
-                ListenableFuture<S> future = task.call();
-                future.addListener(() -> {
-                    try {
-                        wrappedFuture.complete(future.get());
-                        execution.complete(wrappedFuture);
-                    } catch (Exception error) {
-                        if (Errors.isInvalidTokenError(error)) {
-                            authCredential().refresh();
-                        }
-                        if (!execution.retryOn(error)) {
-                            // permanent failure
-                            wrappedFuture.completeExceptionally(error);
-                        }
-                    }
-                }, executorService);
-            }).thenCompose(f -> f.thenApply(resultConvert));
+        return this.vertx;
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/ClusterImpl.java

@@ -56,14 +56,26 @@ final class ClusterImpl extends Impl implements Cluster {
     }
 
     /**
-     * add a new member into the cluster.
+     * add a non-learner new member into the cluster.
      *
      * @param peerAddrs the peer addresses of the new member
      */
     @Override
     public CompletableFuture<MemberAddResponse> addMember(List<URI> peerAddrs) {
+        return addMember(peerAddrs, false);
+    }
+
+    /**
+     * add a new member into the cluster.
+     *
+     * @param peerAddrs the peer addresses of the new member
+     * @param isLearner whether the member is raft learner
+     */
+    @Override
+    public CompletableFuture<MemberAddResponse> addMember(List<URI> peerAddrs, boolean isLearner) {
         MemberAddRequest memberAddRequest = MemberAddRequest.newBuilder()
             .addAllPeerURLs(peerAddrs.stream().map(URI::toString).collect(Collectors.toList()))
+            .setIsLearner(isLearner)
             .build();
 
         return completable(

jetcd-core/src/main/java/io/etcd/jetcd/impl/ElectionImpl.java

@@ -25,7 +25,6 @@ import io.etcd.jetcd.api.LeaderRequest;
 import io.etcd.jetcd.api.ProclaimRequest;
 import io.etcd.jetcd.api.ResignRequest;
 import io.etcd.jetcd.api.VertxElectionGrpc;
-import io.etcd.jetcd.common.exception.EtcdExceptionFactory;
 import io.etcd.jetcd.election.CampaignResponse;
 import io.etcd.jetcd.election.LeaderKey;
 import io.etcd.jetcd.election.LeaderResponse;
@@ -33,13 +32,14 @@ import io.etcd.jetcd.election.NoLeaderException;
 import io.etcd.jetcd.election.NotLeaderException;
 import io.etcd.jetcd.election.ProclaimResponse;
 import io.etcd.jetcd.election.ResignResponse;
+import io.etcd.jetcd.support.Errors;
 import io.etcd.jetcd.support.Util;
 import io.grpc.StatusRuntimeException;
 
 import com.google.protobuf.ByteString;
 
-import static com.google.common.base.Preconditions.checkNotNull;
 import static io.etcd.jetcd.common.exception.EtcdExceptionFactory.toEtcdException;
+import static java.util.Objects.requireNonNull;
 
 final class ElectionImpl extends Impl implements Election {
     private final VertxElectionGrpc.ElectionVertxStub stub;
@@ -52,10 +52,31 @@ final class ElectionImpl extends Impl implements Election {
         this.namespace = connectionManager.getNamespace();
     }
 
+    // Election operations are done in a context where a client is trying to implement
+    // some fault tolerance related use case; in that type of context, it makes sense to always
+    // apply require leader, since we don't want a client connected to a non-raft-leader server
+    // have an election method just go silent if the server the client happens to be connected to
+    // becomes partitioned from the actual raft-leader server in the etcd servers cluster:
+    // in that scenario and without required leader, an attempt to campaign could block forever
+    // not because some other client is already an election leader, but because the server the client
+    // is connected to is partitioned and can't tell.
+    // With require leader, in that case the call will fail and we give
+    // the client the ability to (a) know (b) retry on a different server.
+    // The retry on a different server should happen automatically if the connection manager is using
+    // a round robin strategy.
+    //
+    // Beware in the context of this election API, the word "leader" is overloaded.
+    // In the paragraph above when we say "raft-leader" we are talking about the etcd server that is a leader
+    // of the etcd servers cluster according to raft, we are not talking about the client that
+    // happens to be the leader of an election using the election API in this file.
+    private VertxElectionGrpc.ElectionVertxStub stubWithLeader() {
+        return Util.applyRequireLeader(true, stub);
+    }
+
     @Override
     public CompletableFuture<CampaignResponse> campaign(ByteSequence electionName, long leaseId, ByteSequence proposal) {
-        checkNotNull(electionName, "election name should not be null");
-        checkNotNull(proposal, "proposal should not be null");
+        requireNonNull(electionName, "election name should not be null");
+        requireNonNull(proposal, "proposal should not be null");
 
         CampaignRequest request = CampaignRequest.newBuilder()
             .setName(Util.prefixNamespace(electionName, namespace))
@@ -63,16 +84,17 @@ final class ElectionImpl extends Impl implements Election {
             .setLease(leaseId)
             .build();
 
-        return completable(
-            stub.campaign(request),
-            CampaignResponse::new,
-            this::convertException);
+        return wrapConvertException(
+            execute(
+                () -> stubWithLeader().campaign(request),
+                CampaignResponse::new,
+                Errors::isRetryableForNoSafeRedoOp));
     }
 
     @Override
     public CompletableFuture<ProclaimResponse> proclaim(LeaderKey leaderKey, ByteSequence proposal) {
-        checkNotNull(leaderKey, "leader key should not be null");
-        checkNotNull(proposal, "proposal should not be null");
+        requireNonNull(leaderKey, "leader key should not be null");
+        requireNonNull(proposal, "proposal should not be null");
 
         ProclaimRequest request = ProclaimRequest.newBuilder()
             .setLeader(
@@ -85,44 +107,46 @@ final class ElectionImpl extends Impl implements Election {
             .setValue(ByteString.copyFrom(proposal.getBytes()))
             .build();
 
-        return completable(
-            stub.proclaim(request),
-            ProclaimResponse::new,
-            this::convertException);
+        return wrapConvertException(
+            execute(
+                () -> stubWithLeader().proclaim(request),
+                ProclaimResponse::new,
+                Errors::isRetryableForNoSafeRedoOp));
     }
 
     @Override
     public CompletableFuture<LeaderResponse> leader(ByteSequence electionName) {
-        checkNotNull(electionName, "election name should not be null");
+        requireNonNull(electionName, "election name should not be null");
 
         LeaderRequest request = LeaderRequest.newBuilder()
             .setName(Util.prefixNamespace(electionName, namespace))
             .build();
 
-        return completable(
-            stub.leader(request),
-            r -> new LeaderResponse(r, namespace),
-            this::convertException);
+        return wrapConvertException(
+            execute(
+                () -> stubWithLeader().leader(request),
+                response -> new LeaderResponse(response, namespace),
+                Errors::isRetryableForNoSafeRedoOp));
     }
 
     @Override
     public void observe(ByteSequence electionName, Listener listener) {
-        checkNotNull(electionName, "election name should not be null");
-        checkNotNull(listener, "listener should not be null");
+        requireNonNull(electionName, "election name should not be null");
+        requireNonNull(listener, "listener should not be null");
 
         LeaderRequest request = LeaderRequest.newBuilder()
-            .setName(ByteString.copyFrom(electionName.getBytes()))
+            .setName(Util.prefixNamespace(electionName, namespace))
             .build();
 
-        stub.observe(request)
-            .handler(value -> listener.onNext(new LeaderResponse(value, namespace)))
-            .endHandler(ignored -> listener.onCompleted())
-            .exceptionHandler(error -> listener.onError(EtcdExceptionFactory.toEtcdException(error)));
+        stubWithLeader().observeWithHandler(request,
+            value -> listener.onNext(new LeaderResponse(value, namespace)),
+            ignored -> listener.onCompleted(),
+            error -> listener.onError(toEtcdException(error)));
     }
 
     @Override
     public CompletableFuture<ResignResponse> resign(LeaderKey leaderKey) {
-        checkNotNull(leaderKey, "leader key should not be null");
+        requireNonNull(leaderKey, "leader key should not be null");
 
         ResignRequest request = ResignRequest.newBuilder()
             .setLeader(
@@ -134,25 +158,42 @@ final class ElectionImpl extends Impl implements Election {
                     .build())
             .build();
 
-        return completable(
-            stub.resign(request),
-            ResignResponse::new,
-            this::convertException);
+        return wrapConvertException(
+            execute(
+                () -> stubWithLeader().resign(request),
+                ResignResponse::new,
+                Errors::isRetryableForNoSafeRedoOp));
     }
 
-    private Throwable convertException(Throwable e) {
-        if (e instanceof StatusRuntimeException) {
-            StatusRuntimeException exception = (StatusRuntimeException) e;
-            String description = exception.getStatus().getDescription();
-            // different APIs use different messages. we cannot distinguish missing leader error otherwise,
-            // because communicated status is always UNKNOWN
-            if ("election: not leader".equals(description)) {
-                return NotLeaderException.INSTANCE;
-            } else if ("election: no leader".equals(description)) {
-                return NoLeaderException.INSTANCE;
-            }
-        }
+    private <S> CompletableFuture<S> wrapConvertException(CompletableFuture<S> future) {
+        return future.exceptionally(e -> {
+            throw convertException(e);
+        });
+    }
 
+    private RuntimeException convertException(Throwable e) {
+        Throwable cause = e;
+        while (cause != null) {
+            if (cause instanceof StatusRuntimeException) {
+                StatusRuntimeException exception = (StatusRuntimeException) cause;
+                String description = exception.getStatus().getDescription();
+                // different APIs use different messages. we cannot distinguish missing leader error otherwise,
+                // because communicated status is always UNKNOWN
+                if ("election: not leader".equals(description)) {
+                    // Candidate is not a leader at the moment.
+                    // Note there is a one letter difference, but this exception type is not the same as
+                    // NoLeaderException.
+                    return new NotLeaderException();
+                }
+                if ("election: no leader".equals(description)) {
+                    // Leader for given election does not exist.
+                    // Note there is a one letter difference, but this exception type is not the same as
+                    // NotLeaderException.
+                    return new NoLeaderException();
+                }
+            }
+            cause = cause.getCause();
+        }
         return toEtcdException(e);
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/Impl.java

@@ -13,9 +13,11 @@ import io.etcd.jetcd.support.Errors;
 import io.grpc.Status;
 import io.vertx.core.Future;
 
-import net.jodah.failsafe.Failsafe;
-import net.jodah.failsafe.RetryPolicy;
+import dev.failsafe.Failsafe;
+import dev.failsafe.RetryPolicy;
+import dev.failsafe.RetryPolicyBuilder;
 
+import static io.etcd.jetcd.support.Errors.isAuthStoreExpired;
 import static io.etcd.jetcd.support.Errors.isInvalidTokenError;
 
 abstract class Impl {
@@ -87,9 +89,11 @@ abstract class Impl {
      */
     protected <S, T> CompletableFuture<T> execute(
         Supplier<Future<S>> supplier,
-        Function<S, T> resultConvert) {
+        Function<S, T> resultConvert,
+        boolean autoRetry) {
 
-        return execute(supplier, resultConvert, Errors::isRetryable);
+        return execute(supplier, resultConvert,
+            autoRetry ? Errors::isRetryableForSafeRedoOp : Errors::isRetryableForNoSafeRedoOp);
     }
 
     /**
@@ -107,28 +111,50 @@ abstract class Impl {
         Function<S, T> resultConvert,
         Predicate<Status> doRetry) {
 
-        RetryPolicy<S> retryPolicy = new RetryPolicy<S>()
+        return Failsafe
+            .with(retryPolicy(doRetry))
+            .with(connectionManager.getExecutorService())
+            .getStageAsync(() -> supplier.get().toCompletionStage())
+            .thenApply(resultConvert);
+    }
+
+    protected <S> RetryPolicy<S> retryPolicy(Predicate<Status> doRetry) {
+        RetryPolicyBuilder<S> policy = RetryPolicy.<S> builder()
+            .onFailure(e -> {
+                logger.warn("retry failure (attempt: {}, error: {})",
+                    e.getAttemptCount(),
+                    e.getException() != null ? e.getException().getMessage() : "<none>");
+            })
+            .onRetry(e -> {
+                logger.debug("retry (attempt: {}, error: {})",
+                    e.getAttemptCount(),
+                    e.getLastException() != null ? e.getLastException().getMessage() : "<none>");
+            })
+            .onRetriesExceeded(e -> {
+                logger.warn("maximum number of auto retries reached (attempt: {}, error: {})",
+                    e.getAttemptCount(),
+                    e.getException() != null ? e.getException().getMessage() : "<none>");
+            })
             .handleIf(throwable -> {
                 Status status = Status.fromThrowable(throwable);
                 if (isInvalidTokenError(status)) {
                     connectionManager.authCredential().refresh();
                 }
+                if (isAuthStoreExpired(status)) {
+                    connectionManager.authCredential().refresh();
+                }
                 return doRetry.test(status);
             })
-            .onRetriesExceeded(e -> logger.warn("maximum number of auto retries reached"))
+            .withMaxRetries(connectionManager.builder().retryMaxAttempts())
             .withBackoff(
                 connectionManager.builder().retryDelay(),
                 connectionManager.builder().retryMaxDelay(),
                 connectionManager.builder().retryChronoUnit());
 
         if (connectionManager.builder().retryMaxDuration() != null) {
-            retryPolicy = retryPolicy.withMaxDuration(connectionManager.builder().retryMaxDuration());
+            policy = policy.withMaxDuration(connectionManager.builder().retryMaxDuration());
         }
 
-        return Failsafe
-            .with(retryPolicy)
-            .with(connectionManager.getExecutorService())
-            .getStageAsync(() -> supplier.get().toCompletionStage())
-            .thenApply(resultConvert);
+        return policy.build();
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/KVImpl.java

@@ -33,10 +33,11 @@ import io.etcd.jetcd.options.CompactOption;
 import io.etcd.jetcd.options.DeleteOption;
 import io.etcd.jetcd.options.GetOption;
 import io.etcd.jetcd.options.PutOption;
+import io.etcd.jetcd.options.TxnOption;
 import io.etcd.jetcd.support.Errors;
 import io.etcd.jetcd.support.Requests;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 /**
  * Implementation of etcd kv client.
@@ -59,13 +60,13 @@ final class KVImpl extends Impl implements KV {
 
     @Override
     public CompletableFuture<PutResponse> put(ByteSequence key, ByteSequence value, PutOption option) {
-        checkNotNull(key, "key should not be null");
-        checkNotNull(value, "value should not be null");
-        checkNotNull(option, "option should not be null");
+        requireNonNull(key, "key should not be null");
+        requireNonNull(value, "value should not be null");
+        requireNonNull(option, "option should not be null");
         return execute(
             () -> stub.put(Requests.mapPutRequest(key, value, option, namespace)),
             response -> new PutResponse(response, namespace),
-            Errors::isRetryable);
+            option.isAutoRetry() ? Errors::isRetryableForSafeRedoOp : Errors::isRetryableForNoSafeRedoOp);
     }
 
     @Override
@@ -75,13 +76,13 @@ final class KVImpl extends Impl implements KV {
 
     @Override
     public CompletableFuture<GetResponse> get(ByteSequence key, GetOption option) {
-        checkNotNull(key, "key should not be null");
-        checkNotNull(option, "option should not be null");
+        requireNonNull(key, "key should not be null");
+        requireNonNull(option, "option should not be null");
 
         return execute(
             () -> stub.range(Requests.mapRangeRequest(key, option, namespace)),
             response -> new GetResponse(response, namespace),
-            Errors::isRetryable);
+            Errors::isRetryableForSafeRedoOp);
     }
 
     @Override
@@ -91,13 +92,13 @@ final class KVImpl extends Impl implements KV {
 
     @Override
     public CompletableFuture<DeleteResponse> delete(ByteSequence key, DeleteOption option) {
-        checkNotNull(key, "key should not be null");
-        checkNotNull(option, "option should not be null");
+        requireNonNull(key, "key should not be null");
+        requireNonNull(option, "option should not be null");
 
         return execute(
             () -> stub.deleteRange(Requests.mapDeleteRequest(key, option, namespace)),
             response -> new DeleteResponse(response, namespace),
-            Errors::isRetryable);
+            option.isAutoRetry() ? Errors::isRetryableForSafeRedoOp : Errors::isRetryableForNoSafeRedoOp);
     }
 
     @Override
@@ -107,7 +108,7 @@ final class KVImpl extends Impl implements KV {
 
     @Override
     public CompletableFuture<CompactResponse> compact(long rev, CompactOption option) {
-        checkNotNull(option, "option should not be null");
+        requireNonNull(option, "option should not be null");
 
         CompactionRequest request = CompactionRequest.newBuilder()
             .setRevision(rev).setPhysical(option.isPhysical())
@@ -116,15 +117,21 @@ final class KVImpl extends Impl implements KV {
         return execute(
             () -> stub.compact(request),
             CompactResponse::new,
-            Errors::isRetryable);
+            Errors::isRetryableForSafeRedoOp);
     }
 
     @Override
     public Txn txn() {
+        return txn(TxnOption.DEFAULT);
+    }
+
+    @Override
+    public Txn txn(TxnOption option) {
         return TxnImpl.newTxn(
             request -> execute(
                 () -> stub.txn(request),
-                response -> new TxnResponse(response, namespace), Errors::isRetryable),
+                response -> new TxnResponse(response, namespace),
+                option.isAutoRetry() ? Errors::isRetryableForSafeRedoOp : Errors::isRetryableForNoSafeRedoOp),
             namespace);
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/LeaseImpl.java

@@ -16,15 +16,15 @@
 
 package io.etcd.jetcd.impl;
 
+import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import io.etcd.jetcd.Lease;
 import io.etcd.jetcd.api.LeaseGrantRequest;
@@ -44,10 +44,10 @@ import io.etcd.jetcd.support.Util;
 import io.grpc.stub.StreamObserver;
 import io.vertx.core.streams.WriteStream;
 
-import static com.google.common.base.Preconditions.checkNotNull;
 import static io.etcd.jetcd.common.exception.EtcdExceptionFactory.newClosedLeaseClientException;
 import static io.etcd.jetcd.common.exception.EtcdExceptionFactory.newEtcdException;
 import static io.etcd.jetcd.common.exception.EtcdExceptionFactory.toEtcdException;
+import static java.util.Objects.requireNonNull;
 
 /**
  * Implementation of lease client.
@@ -84,7 +84,8 @@ final class LeaseImpl extends Impl implements Lease {
                 LeaseGrantRequest.newBuilder()
                     .setTTL(ttl)
                     .build()),
-            LeaseGrantResponse::new);
+            LeaseGrantResponse::new,
+            true);
     }
 
     @Override
@@ -94,7 +95,8 @@ final class LeaseImpl extends Impl implements Lease {
                 LeaseGrantRequest.newBuilder()
                     .setTTL(ttl)
                     .build()),
-            LeaseGrantResponse::new);
+            LeaseGrantResponse::new,
+            true);
     }
 
     @Override
@@ -104,12 +106,13 @@ final class LeaseImpl extends Impl implements Lease {
                 LeaseRevokeRequest.newBuilder()
                     .setID(leaseId)
                     .build()),
-            LeaseRevokeResponse::new);
+            LeaseRevokeResponse::new,
+            true);
     }
 
     @Override
     public CompletableFuture<LeaseTimeToLiveResponse> timeToLive(long leaseId, LeaseOption option) {
-        checkNotNull(option, "LeaseOption should not be null");
+        requireNonNull(option, "LeaseOption should not be null");
 
         LeaseTimeToLiveRequest leaseTimeToLiveRequest = LeaseTimeToLiveRequest.newBuilder()
             .setID(leaseId)
@@ -118,7 +121,8 @@ final class LeaseImpl extends Impl implements Lease {
 
         return execute(
             () -> this.stub.leaseTimeToLive(leaseTimeToLiveRequest),
-            LeaseTimeToLiveResponse::new);
+            LeaseTimeToLiveResponse::new,
+            true);
     }
 
     @Override
@@ -143,27 +147,28 @@ final class LeaseImpl extends Impl implements Lease {
 
     @Override
     public CompletableFuture<LeaseKeepAliveResponse> keepAliveOnce(long leaseId) {
+        final AtomicReference<WriteStream<LeaseKeepAliveRequest>> ref = new AtomicReference<>();
         final CompletableFuture<LeaseKeepAliveResponse> future = new CompletableFuture<>();
+        final LeaseKeepAliveRequest req = LeaseKeepAliveRequest.newBuilder().setID(leaseId).build();
 
-        final CloseableClient ka = keepAlive(leaseId, new StreamObserver<LeaseKeepAliveResponse>() {
-            @Override
-            public void onNext(LeaseKeepAliveResponse value) {
-                future.complete(value);
-            }
+        leaseStub
+            .leaseKeepAliveWithHandler(
+                s -> {
+                    ref.set(s);
+                    s.write(req);
+                },
+                r -> {
+                    if (r.getTTL() != 0) {
+                        future.complete(new LeaseKeepAliveResponse(r));
+                    } else {
+                        future.completeExceptionally(
+                            newEtcdException(ErrorCode.NOT_FOUND, "etcdserver: requested lease not found"));
+                    }
+                },
+                null,
+                future::completeExceptionally);
 
-            @Override
-            public void onError(Throwable t) {
-                future.completeExceptionally(toEtcdException(t));
-            }
-
-            @Override
-            public void onCompleted() {
-            }
-        });
-
-        return future.whenCompleteAsync(
-            (val, throwable) -> ka.close(),
-            connectionManager().getExecutorService());
+        return future.whenComplete((r, t) -> ref.get().end(req));
     }
 
     @Override
@@ -186,20 +191,20 @@ final class LeaseImpl extends Impl implements Lease {
      * The KeepAliver hold a background task and stream for keep aliaves.
      */
     private final class KeepAlive extends Service {
-        private volatile ScheduledFuture<?> task;
-        private volatile ScheduledFuture<?> restart;
-        private volatile ScheduledExecutorService executor;
-        private volatile WriteStream<io.etcd.jetcd.api.LeaseKeepAliveRequest> requestStream;
+        private volatile Long task;
+        private volatile Long restart;
+        private volatile WriteStream<LeaseKeepAliveRequest> requestStream;
 
         public KeepAlive() {
-            this.executor = Executors.newScheduledThreadPool(2);
         }
 
         @Override
         public void doStart() {
-            leaseStub.leaseKeepAlive(this::writeHandler)
-                .handler(this::handleResponse)
-                .exceptionHandler(this::handleException);
+            leaseStub.leaseKeepAliveWithHandler(
+                this::writeHandler,
+                this::handleResponse,
+                null,
+                this::handleException);
         }
 
         @Override
@@ -208,12 +213,10 @@ final class LeaseImpl extends Impl implements Lease {
                 requestStream.end();
             }
             if (this.restart != null) {
-                this.restart.cancel(true);
-                this.restart = null;
+                connectionManager().vertx().cancelTimer(this.restart);
             }
             if (this.task != null) {
-                this.task.cancel(true);
-                this.task = null;
+                connectionManager().vertx().cancelTimer(this.task);
             }
         }
 
@@ -223,20 +226,20 @@ final class LeaseImpl extends Impl implements Lease {
 
             this.task = null;
             this.restart = null;
-            this.executor.shutdownNow();
         }
 
-        private void writeHandler(WriteStream<io.etcd.jetcd.api.LeaseKeepAliveRequest> stream) {
+        private void writeHandler(WriteStream<LeaseKeepAliveRequest> stream) {
             requestStream = stream;
 
-            task = executor.scheduleAtFixedRate(
-                () -> keepAlives.values().forEach(element -> sendKeepAlive(element, stream)),
+            task = connectionManager().vertx().setPeriodic(
                 0,
                 500,
-                TimeUnit.MILLISECONDS);
+                l -> {
+                    keepAlives.values().forEach(element -> sendKeepAlive(element, stream));
+                });
         }
 
-        private void sendKeepAlive(KeepAliveObserver observer, WriteStream<io.etcd.jetcd.api.LeaseKeepAliveRequest> stream) {
+        private void sendKeepAlive(KeepAliveObserver observer, WriteStream<LeaseKeepAliveRequest> stream) {
             if (observer.getNextKeepAlive() < System.currentTimeMillis()) {
                 stream.write(
                     LeaseKeepAliveRequest.newBuilder().setID(observer.getLeaseId()).build());
@@ -267,12 +270,20 @@ final class LeaseImpl extends Impl implements Lease {
             }
         }
 
-        private synchronized void handleException(Throwable r) {
+        private synchronized void handleException(Throwable throwable) {
             if (!this.isRunning()) {
                 return;
             }
 
-            restart = this.executor.schedule(this::restart, 500, TimeUnit.MILLISECONDS);
+            keepAlives.values().forEach(ka -> ka.onError(throwable));
+
+            restart = connectionManager().vertx().setTimer(
+                500,
+                l -> {
+                    if (isRunning()) {
+                        restart();
+                    }
+                });
         }
     }
 
@@ -280,42 +291,35 @@ final class LeaseImpl extends Impl implements Lease {
      * The DeadLiner hold a background task to check deadlines.
      */
     private class DeadLine extends Service {
-        private volatile ScheduledFuture<?> task;
-        private volatile ScheduledExecutorService executor;
+        private volatile Long task;
 
         public DeadLine() {
-            this.executor = Executors.newScheduledThreadPool(2);
         }
 
         @Override
         public void doStart() {
-            this.task = executor.scheduleAtFixedRate(() -> {
-                long now = System.currentTimeMillis();
+            this.task = connectionManager().vertx().setPeriodic(
+                0,
+                1000,
+                l -> {
+                    long now = System.currentTimeMillis();
 
-                keepAlives.values().removeIf(ka -> {
-                    if (ka.getDeadLine() < now) {
-                        ka.onCompleted();
-                        return true;
-                    }
-                    return false;
+                    keepAlives.values().removeIf(ka -> {
+                        if (ka.getDeadLine() < now) {
+                            ka.onCompleted();
+                            return true;
+                        }
+                        return false;
+                    });
                 });
-            }, 0, 1000, TimeUnit.MILLISECONDS);
         }
 
         @Override
         public void doStop() {
             if (this.task != null) {
-                this.task.cancel(true);
+                connectionManager().vertx().cancelTimer(this.task);
             }
         }
-
-        @Override
-        public void close() {
-            super.close();
-
-            this.executor.shutdownNow();
-        }
-
     }
 
     /**
@@ -329,6 +333,10 @@ final class LeaseImpl extends Impl implements Lease {
         private long nextKeepAlive;
 
         public KeepAliveObserver(long leaseId) {
+            this(leaseId, Collections.emptyList());
+        }
+
+        public KeepAliveObserver(long leaseId, Collection<StreamObserver<LeaseKeepAliveResponse>> observers) {
             this.nextKeepAlive = System.currentTimeMillis();
 
             // Use user-provided timeout if present to avoid removing KeepAlive before first response from server
@@ -337,7 +345,7 @@ final class LeaseImpl extends Impl implements Lease {
                 : DEFAULT_FIRST_KEEPALIVE_TIMEOUT_MS;
             this.deadLine = nextKeepAlive + initialKeepAliveTimeoutMs;
 
-            this.observers = new CopyOnWriteArrayList<>();
+            this.observers = new CopyOnWriteArrayList<>(observers);
             this.leaseId = leaseId;
         }
 

jetcd-core/src/main/java/io/etcd/jetcd/impl/LockImpl.java

@@ -28,12 +28,28 @@ import io.etcd.jetcd.lock.UnlockResponse;
 import io.etcd.jetcd.support.Errors;
 import io.etcd.jetcd.support.Util;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 final class LockImpl extends Impl implements Lock {
     private final VertxLockGrpc.LockVertxStub stub;
     private final ByteSequence namespace;
 
+    // Lock operations are done in a context where a client is trying to implement
+    // some strict mutual exclusion use case; in that type of context, it makes sense to always
+    // apply require leader, since we don't want a client connected to a non-raft-leader server
+    // to have a lock method just go silent if the server the client happens to be connected to
+    // becomes partitioned from the actual raft-leader server in the etcd servers cluster:
+    // in that scenario and without required leader, an attempt to lock could block forever
+    // not because some other client is already holding a lock, but because the server the client
+    // is connected to is partitioned and can't tell.
+    // With require leader, in that case the call will fail and the client has the ability to
+    // (a) know (b) retry on a different server.
+    // The retry on a different server should happen automatically if the connection manager is using
+    // a round robin strategy.
+    private VertxLockGrpc.LockVertxStub stubWithLeader() {
+        return Util.applyRequireLeader(true, stub);
+    }
+
     LockImpl(ClientConnectionManager connectionManager) {
         super(connectionManager);
 
@@ -43,7 +59,7 @@ final class LockImpl extends Impl implements Lock {
 
     @Override
     public CompletableFuture<LockResponse> lock(ByteSequence name, long leaseId) {
-        checkNotNull(name);
+        requireNonNull(name);
 
         LockRequest request = LockRequest.newBuilder()
             .setName(Util.prefixNamespace(name, namespace))
@@ -51,22 +67,22 @@ final class LockImpl extends Impl implements Lock {
             .build();
 
         return execute(
-            () -> stub.lock(request),
+            () -> stubWithLeader().lock(request),
             response -> new LockResponse(response, namespace),
-            Errors::isRetryable);
+            Errors::isRetryableForSafeRedoOp);
     }
 
     @Override
     public CompletableFuture<UnlockResponse> unlock(ByteSequence lockKey) {
-        checkNotNull(lockKey);
+        requireNonNull(lockKey);
 
         UnlockRequest request = UnlockRequest.newBuilder()
             .setKey(Util.prefixNamespace(lockKey, namespace))
             .build();
 
         return execute(
-            () -> stub.unlock(request),
+            () -> stubWithLeader().unlock(request),
             UnlockResponse::new,
-            Errors::isRetryable);
+            Errors::isRetryableForSafeRedoOp);
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/MaintenanceImpl.java

@@ -18,26 +18,17 @@ package io.etcd.jetcd.impl;
 
 import java.io.IOException;
 import java.io.OutputStream;
-import java.net.URI;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicLong;
 
 import io.etcd.jetcd.Maintenance;
-import io.etcd.jetcd.api.AlarmRequest;
+import io.etcd.jetcd.api.*;
 import io.etcd.jetcd.api.AlarmType;
-import io.etcd.jetcd.api.DefragmentRequest;
-import io.etcd.jetcd.api.HashKVRequest;
-import io.etcd.jetcd.api.MaintenanceGrpc;
-import io.etcd.jetcd.api.MoveLeaderRequest;
-import io.etcd.jetcd.api.SnapshotRequest;
-import io.etcd.jetcd.api.StatusRequest;
-import io.etcd.jetcd.api.VertxMaintenanceGrpc;
 import io.etcd.jetcd.maintenance.AlarmResponse;
 import io.etcd.jetcd.maintenance.DefragmentResponse;
 import io.etcd.jetcd.maintenance.HashKVResponse;
 import io.etcd.jetcd.maintenance.MoveLeaderResponse;
 import io.etcd.jetcd.maintenance.StatusResponse;
-import io.etcd.jetcd.support.Util;
 import io.grpc.stub.StreamObserver;
 
 import static com.google.common.base.Preconditions.checkArgument;
@@ -80,50 +71,28 @@ final class MaintenanceImpl extends Impl implements Maintenance {
         return completable(this.stub.alarm(alarmRequest), AlarmResponse::new);
     }
 
-    @Override
-    public CompletableFuture<DefragmentResponse> defragmentMember(URI endpoint) {
-        return this.connectionManager().withNewChannel(
-            // TODO
-            endpoint.toString(),
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.defragment(DefragmentRequest.getDefaultInstance()),
-                DefragmentResponse::new,
-                this.connectionManager().getExecutorService()));
-    }
-
     @Override
     public CompletableFuture<DefragmentResponse> defragmentMember(String target) {
         return this.connectionManager().withNewChannel(
             target,
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.defragment(DefragmentRequest.getDefaultInstance()),
-                DefragmentResponse::new,
-                this.connectionManager().getExecutorService()));
-    }
-
-    @Override
-    public CompletableFuture<StatusResponse> statusMember(URI endpoint) {
-        return this.connectionManager().withNewChannel(
-            // TODO
-            endpoint.toString(),
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.status(StatusRequest.getDefaultInstance()),
-                StatusResponse::new,
-                this.connectionManager().getExecutorService()));
+            VertxMaintenanceGrpc::newVertxStub,
+            stub -> {
+                return stub.defragment(DefragmentRequest.getDefaultInstance())
+                    .map(DefragmentResponse::new)
+                    .toCompletionStage().toCompletableFuture();
+            });
     }
 
     @Override
     public CompletableFuture<StatusResponse> statusMember(String target) {
         return this.connectionManager().withNewChannel(
             target,
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.status(StatusRequest.getDefaultInstance()),
-                StatusResponse::new,
-                this.connectionManager().getExecutorService()));
+            VertxMaintenanceGrpc::newVertxStub,
+            stub -> {
+                return stub.status(StatusRequest.getDefaultInstance())
+                    .map(StatusResponse::new)
+                    .toCompletionStage().toCompletableFuture();
+            });
     }
 
     @Override
@@ -133,27 +102,16 @@ final class MaintenanceImpl extends Impl implements Maintenance {
             MoveLeaderResponse::new);
     }
 
-    @Override
-    public CompletableFuture<HashKVResponse> hashKV(URI endpoint, long rev) {
-        return this.connectionManager().withNewChannel(
-            // TODO
-            endpoint.toString(),
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.hashKV(HashKVRequest.newBuilder().setRevision(rev).build()),
-                HashKVResponse::new,
-                this.connectionManager().getExecutorService()));
-    }
-
     @Override
     public CompletableFuture<HashKVResponse> hashKV(String target, long rev) {
         return this.connectionManager().withNewChannel(
             target,
-            MaintenanceGrpc::newFutureStub,
-            stub -> Util.toCompletableFuture(
-                stub.hashKV(HashKVRequest.newBuilder().setRevision(rev).build()),
-                HashKVResponse::new,
-                this.connectionManager().getExecutorService()));
+            VertxMaintenanceGrpc::newVertxStub,
+            stub -> {
+                return stub.hashKV(HashKVRequest.newBuilder().setRevision(rev).build())
+                    .map(HashKVResponse::new)
+                    .toCompletionStage().toCompletableFuture();
+            });
     }
 
     @Override
@@ -161,19 +119,20 @@ final class MaintenanceImpl extends Impl implements Maintenance {
         final CompletableFuture<Long> answer = new CompletableFuture<>();
         final AtomicLong bytes = new AtomicLong(0);
 
-        this.stub.snapshot(SnapshotRequest.getDefaultInstance())
-            .handler(r -> {
+        this.stub.snapshotWithHandler(
+            SnapshotRequest.getDefaultInstance(),
+            r -> {
                 try {
                     r.getBlob().writeTo(outputStream);
                     bytes.addAndGet(r.getBlob().size());
                 } catch (IOException e) {
                     answer.completeExceptionally(toEtcdException(e));
                 }
-            })
-            .endHandler(event -> {
+            },
+            event -> {
                 answer.complete(bytes.get());
-            })
-            .exceptionHandler(e -> {
+            },
+            e -> {
                 answer.completeExceptionally(toEtcdException(e));
             });
 
@@ -183,9 +142,10 @@ final class MaintenanceImpl extends Impl implements Maintenance {
     @Override
     public void snapshot(StreamObserver<io.etcd.jetcd.maintenance.SnapshotResponse> observer) {
 
-        this.stub.snapshot(SnapshotRequest.getDefaultInstance())
-            .handler(r -> observer.onNext(new io.etcd.jetcd.maintenance.SnapshotResponse(r)))
-            .endHandler(event -> observer.onCompleted())
-            .exceptionHandler(e -> observer.onError(toEtcdException(e)));
+        this.stub.snapshotWithHandler(
+            SnapshotRequest.getDefaultInstance(),
+            r -> observer.onNext(new io.etcd.jetcd.maintenance.SnapshotResponse(r)),
+            event -> observer.onCompleted(),
+            e -> observer.onError(toEtcdException(e)));
     }
 }

jetcd-core/src/main/java/io/etcd/jetcd/impl/WatchImpl.java

@@ -41,7 +41,6 @@ import io.etcd.jetcd.options.WatchOption;
 import io.etcd.jetcd.support.Errors;
 import io.etcd.jetcd.support.Util;
 import io.grpc.Status;
-import io.vertx.core.streams.ReadStream;
 import io.vertx.core.streams.WriteStream;
 
 import com.google.common.base.Strings;
@@ -73,7 +72,9 @@ final class WatchImpl extends Impl implements Watch {
 
         this.lock = new Object();
         this.stub = connectionManager.newStub(VertxWatchGrpc::newVertxStub);
-        this.executor = MoreExecutors.listeningDecorator(Executors.newScheduledThreadPool(1));
+        // set it to daemon as there is no way for users to create this thread pool by their own
+        this.executor = MoreExecutors.listeningDecorator(
+            Executors.newScheduledThreadPool(1, Util.createThreadFactory("jetcd-watch-", true)));
         this.closed = new AtomicBoolean();
         this.watchers = new CopyOnWriteArrayList<>();
         this.namespace = connectionManager.getNamespace();
@@ -122,10 +123,8 @@ final class WatchImpl extends Impl implements Watch {
         private final Listener listener;
         private final AtomicBoolean closed;
 
-        //private StreamObserver<WatchRequest> stream;
-        private AtomicReference<WriteStream<WatchRequest>> wstream;
-        private AtomicBoolean started;
-        private ReadStream<WatchResponse> rstream;
+        private final AtomicReference<WriteStream<WatchRequest>> wstream;
+        private final AtomicBoolean started;
         private long revision;
         private long id;
 
@@ -137,7 +136,6 @@ final class WatchImpl extends Impl implements Watch {
 
             this.started = new AtomicBoolean();
             this.wstream = new AtomicReference<>();
-            this.rstream = null;
             this.id = -1;
             this.revision = this.option.getRevision();
         }
@@ -148,7 +146,8 @@ final class WatchImpl extends Impl implements Watch {
         //
         // ************************
 
-        boolean isClosed() {
+        @Override
+        public boolean isClosed() {
             return this.closed.get() || WatchImpl.this.closed.get();
         }
 
@@ -158,7 +157,7 @@ final class WatchImpl extends Impl implements Watch {
             }
 
             if (started.compareAndSet(false, true)) {
-                // id is not really useful today but it may be in etcd 3.4
+                // id is not really useful today, but it may be in etcd 3.4
                 id = -1;
 
                 WatchCreateRequest.Builder builder = WatchCreateRequest.newBuilder()
@@ -170,7 +169,7 @@ final class WatchImpl extends Impl implements Watch {
                     .map(endKey -> Util.prefixNamespaceToRangeEnd(endKey, namespace))
                     .ifPresent(builder::setRangeEnd);
 
-                if (!option.getEndKey().isPresent() && option.isPrefix()) {
+                if (option.getEndKey().isEmpty() && option.isPrefix()) {
                     ByteSequence endKey = OptionsUtil.prefixEndOf(key);
                     builder.setRangeEnd(Util.prefixNamespaceToRangeEnd(endKey, namespace));
                 }
@@ -183,14 +182,15 @@ final class WatchImpl extends Impl implements Watch {
                     builder.addFilters(WatchCreateRequest.FilterType.NOPUT);
                 }
 
-                rstream = Util.applyRequireLeader(option.withRequireLeader(), stub).watch(stream -> {
-                    wstream.set(stream);
-                    stream.write(WatchRequest.newBuilder().setCreateRequest(builder).build());
-                });
-
-                rstream.handler(this::onNext);
-                rstream.exceptionHandler(this::onError);
-                rstream.endHandler(event -> onCompleted());
+                var ignored = Util.applyRequireLeader(option.withRequireLeader(), stub)
+                    .watchWithHandler(
+                        stream -> {
+                            wstream.set(stream);
+                            stream.write(WatchRequest.newBuilder().setCreateRequest(builder).build());
+                        },
+                        this::onNext,
+                        event -> onCompleted(),
+                        this::onError);
             }
         }
 
@@ -245,7 +245,9 @@ final class WatchImpl extends Impl implements Watch {
 
             // handle a special case when watch has been created and closed at the same time
             if (response.getCreated() && response.getCanceled() && response.getCancelReason() != null
-                && response.getCancelReason().contains("etcdserver: permission denied")) {
+                && (response.getCancelReason().contains("etcdserver: permission denied") ||
+                    response.getCancelReason().contains("etcdserver: invalid auth token"))) {
+
                 // potentially access token expired
                 connectionManager().authCredential().refresh();
                 Status error = Status.Code.CANCELLED.toStatus().withDescription(response.getCancelReason());
@@ -263,6 +265,9 @@ final class WatchImpl extends Impl implements Watch {
 
                 revision = Math.max(revision, response.getHeader().getRevision());
                 id = response.getWatchId();
+                if (option.isCreatedNotify()) {
+                    listener.onNext(new io.etcd.jetcd.watch.WatchResponse(response));
+                }
             } else if (response.getCanceled()) {
 
                 //
@@ -351,8 +356,8 @@ final class WatchImpl extends Impl implements Watch {
         private void reschedule() {
             Futures.addCallback(executor.schedule(this::resume, 500, TimeUnit.MILLISECONDS), new FutureCallback<Object>() {
                 @Override
-                public void onFailure(Throwable throwable) {
-                    LOG.warn("scheduled resume failed", throwable);
+                public void onFailure(Throwable t) {
+                    LOG.warn("scheduled resume failed", t);
                 }
 
                 @Override

jetcd-core/src/main/java/io/etcd/jetcd/kv/DeleteResponse.java

@@ -37,6 +37,8 @@ public class DeleteResponse extends AbstractResponse<DeleteRangeResponse> {
 
     /**
      * Returns the number of keys deleted by the delete range request.
+     *
+     * @return number of deleted items.
      */
     public long getDeleted() {
         return getResponse().getDeleted();
@@ -44,6 +46,8 @@ public class DeleteResponse extends AbstractResponse<DeleteRangeResponse> {
 
     /**
      * Returns previous key-value pairs.
+     *
+     * @return previous kv,
      */
     public synchronized List<KeyValue> getPrevKvs() {
         if (prevKvs == null) {

jetcd-core/src/main/java/io/etcd/jetcd/kv/GetResponse.java

@@ -37,6 +37,8 @@ public class GetResponse extends AbstractResponse<RangeResponse> {
 
     /**
      * Returns a list of key-value pairs matched by the range request.
+     *
+     * @return kvs.
      */
     public synchronized List<KeyValue> getKvs() {
         if (kvs == null) {
@@ -48,13 +50,21 @@ public class GetResponse extends AbstractResponse<RangeResponse> {
 
     /**
      * Returns if there are more keys to return in the requested range.
+     *
+     * @return more.
      */
     public boolean isMore() {
         return getResponse().getMore();
     }
 
     /**
-     * Returns the number of keys within the range when requested.
+     * Returns the number of keys within the range requested.
+     * Note this value is never affected by filtering options (limit, min or max created or modified revisions)
+     * Count is the count for keys on the range part of a request.
+     * Filters for limit and created or modified revision ranges restrict the
+     * returned KVs, but not the count.
+     *
+     * @return count.
      */
     public long getCount() {
         return getResponse().getCount();

jetcd-core/src/main/java/io/etcd/jetcd/kv/PutResponse.java

@@ -31,6 +31,8 @@ public class PutResponse extends AbstractResponse<io.etcd.jetcd.api.PutResponse>
 
     /**
      * Returns previous key-value pair.
+     *
+     * @return prev kv.
      */
     public KeyValue getPrevKv() {
         return new KeyValue(getResponse().getPrevKv(), namespace);
@@ -38,6 +40,8 @@ public class PutResponse extends AbstractResponse<io.etcd.jetcd.api.PutResponse>
 
     /**
      * Returns whether a previous key-value pair is present.
+     *
+     * @return if has prev kv.
      */
     public boolean hasPrevKv() {
         return getResponse().hasPrevKv();

jetcd-core/src/main/java/io/etcd/jetcd/kv/TxnResponse.java

@@ -47,6 +47,8 @@ public class TxnResponse extends AbstractResponse<io.etcd.jetcd.api.TxnResponse>
 
     /**
      * Returns true if the compare evaluated to true or false otherwise.
+     *
+     * @return if succeeded.
      */
     public boolean isSucceeded() {
         return getResponse().getSucceeded();
@@ -54,6 +56,8 @@ public class TxnResponse extends AbstractResponse<io.etcd.jetcd.api.TxnResponse>
 
     /**
      * Returns a list of DeleteResponse; empty list if none.
+     *
+     * @return delete responses.
      */
     public synchronized List<DeleteResponse> getDeleteResponses() {
         if (deleteResponses == null) {
@@ -68,6 +72,8 @@ public class TxnResponse extends AbstractResponse<io.etcd.jetcd.api.TxnResponse>
 
     /**
      * Returns a list of GetResponse; empty list if none.
+     *
+     * @return get responses.
      */
     public synchronized List<GetResponse> getGetResponses() {
         if (getResponses == null) {
@@ -81,6 +87,8 @@ public class TxnResponse extends AbstractResponse<io.etcd.jetcd.api.TxnResponse>
 
     /**
      * Returns a list of PutResponse; empty list if none.
+     *
+     * @return put responses.
      */
     public synchronized List<PutResponse> getPutResponses() {
         if (putResponses == null) {
@@ -94,6 +102,8 @@ public class TxnResponse extends AbstractResponse<io.etcd.jetcd.api.TxnResponse>
 
     /**
      * Returns a list of TxnResponse; empty list if none.
+     *
+     * @return txn responses.
      */
     public synchronized List<TxnResponse> getTxnResponses() {
         if (txnResponses == null) {

jetcd-core/src/main/java/io/etcd/jetcd/lease/LeaseGrantResponse.java

@@ -26,6 +26,8 @@ public class LeaseGrantResponse extends AbstractResponse<io.etcd.jetcd.api.Lease
 
     /**
      * Returns the lease ID for the granted lease.
+     *
+     * @return the id.
      */
     public long getID() {
         return getResponse().getID();
@@ -33,6 +35,8 @@ public class LeaseGrantResponse extends AbstractResponse<io.etcd.jetcd.api.Lease
 
     /**
      * Returns the server chosen lease time-to-live in seconds.
+     *
+     * @return the ttl.
      */
     public long getTTL() {
         return getResponse().getTTL();

jetcd-core/src/main/java/io/etcd/jetcd/lease/LeaseKeepAliveResponse.java

@@ -26,6 +26,8 @@ public class LeaseKeepAliveResponse extends AbstractResponse<io.etcd.jetcd.api.L
 
     /**
      * Returns the lease ID from the keep alive request.
+     *
+     * @return the id.
      */
     public long getID() {
         return getResponse().getID();
@@ -33,6 +35,8 @@ public class LeaseKeepAliveResponse extends AbstractResponse<io.etcd.jetcd.api.L
 
     /**
      * Returns the new time-to-live for the lease.
+     *
+     * @return the ttl.
      */
     public long getTTL() {
         return getResponse().getTTL();

jetcd-core/src/main/java/io/etcd/jetcd/lease/LeaseTimeToLiveResponse.java

@@ -32,6 +32,8 @@ public class LeaseTimeToLiveResponse extends AbstractResponse<io.etcd.jetcd.api.
 
     /**
      * Returns the lease ID from the keep alive request.
+     *
+     * @return the lease id.
      */
     public long getID() {
         return getResponse().getID();
@@ -39,13 +41,17 @@ public class LeaseTimeToLiveResponse extends AbstractResponse<io.etcd.jetcd.api.
 
     /**
      * Returns the remaining TTL in seconds for the lease; the lease will expire in under TTL+1 seconds.
+     *
+     * @return the ttl.
      */
-    public long getTTl() {
+    public long getTTL() {
         return getResponse().getTTL();
     }
 
     /**
      * Returns the initial granted time in seconds upon lease creation/renewal.
+     *
+     * @return the granted ttl.
      */
     public long getGrantedTTL() {
         return getResponse().getGrantedTTL();
@@ -53,6 +59,8 @@ public class LeaseTimeToLiveResponse extends AbstractResponse<io.etcd.jetcd.api.
 
     /**
      * Returns the list of keys attached to this lease.
+     *
+     * @return the keys.
      */
     public synchronized List<ByteSequence> getKeys() {
         if (keys == null) {

jetcd-core/src/main/java/io/etcd/jetcd/lock/LockResponse.java

@@ -33,6 +33,8 @@ public class LockResponse extends AbstractResponse<io.etcd.jetcd.api.lock.LockRe
      * Returns the key that will exist on etcd for the duration that the Lock caller
      * owns the lock. Users should not modify this key or the lock may exhibit
      * undefined behavior.
+     *
+     * @return the key.
      */
     public ByteSequence getKey() {
         return unprefixedKey;

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/AlarmMember.java

@@ -28,6 +28,8 @@ public class AlarmMember {
 
     /**
      * Returns the ID of the member associated with the raised alarm.
+     *
+     * @return the member id.
      */
     public long getMemberId() {
         return memberId;
@@ -36,6 +38,8 @@ public class AlarmMember {
     /**
      *
      * Returns the type of alarm which has been raised.
+     *
+     * @return the alarm type.
      */
     public AlarmType getAlarmType() {
         return alarmType;

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/AlarmResponse.java

@@ -51,6 +51,8 @@ public class AlarmResponse extends AbstractResponse<io.etcd.jetcd.api.AlarmRespo
 
     /**
      * Returns a list of alarms associated with the alarm request.
+     *
+     * @return the alarms.
      */
     public synchronized List<AlarmMember> getAlarms() {
         if (alarms == null) {

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/DefragmentResponse.java

@@ -16,13 +16,11 @@
 
 package io.etcd.jetcd.maintenance;
 
-import java.net.URI;
-
 import io.etcd.jetcd.Maintenance;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * DefragmentResponse returned by {@link Maintenance#defragmentMember(URI)} contains a header.
+ * DefragmentResponse returned by {@link Maintenance#defragmentMember(String)} contains a header.
  */
 public class DefragmentResponse extends AbstractResponse<io.etcd.jetcd.api.DefragmentResponse> {
 

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/HashKVResponse.java

@@ -16,13 +16,11 @@
 
 package io.etcd.jetcd.maintenance;
 
-import java.net.URI;
-
 import io.etcd.jetcd.Maintenance;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * HashKVResponse returned by {@link Maintenance#hashKV(URI, long)}.
+ * HashKVResponse returned by {@link Maintenance#hashKV(String, long)}.
  */
 public class HashKVResponse extends AbstractResponse<io.etcd.jetcd.api.HashKVResponse> {
 
@@ -32,6 +30,8 @@ public class HashKVResponse extends AbstractResponse<io.etcd.jetcd.api.HashKVRes
 
     /**
      * Returns the hash value computed from the responding member's MVCC keys up to a given revision.
+     *
+     * @return the response hash.
      */
     public int getHash() {
         return getResponse().getHash();
@@ -39,6 +39,8 @@ public class HashKVResponse extends AbstractResponse<io.etcd.jetcd.api.HashKVRes
 
     /**
      * Returns the compacted revision of key-value store when hash begins.
+     *
+     * @return if compacted.
      */
     public long getCompacted() {
         return getResponse().getCompactRevision();

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/SnapshotResponse.java

@@ -28,6 +28,8 @@ public class SnapshotResponse extends AbstractResponse<io.etcd.jetcd.api.Snapsho
 
     /**
      * Returns the remaining bytes.
+     *
+     * @return the remaining bytes.
      */
     public long getRemainingBytes() {
         return getResponse().getRemainingBytes();
@@ -35,6 +37,8 @@ public class SnapshotResponse extends AbstractResponse<io.etcd.jetcd.api.Snapsho
 
     /**
      * Returns the blob.
+     *
+     * @return the blob.
      */
     public ByteString getBlob() {
         return getResponse().getBlob();

jetcd-core/src/main/java/io/etcd/jetcd/maintenance/StatusResponse.java

@@ -16,13 +16,11 @@
 
 package io.etcd.jetcd.maintenance;
 
-import java.net.URI;
-
 import io.etcd.jetcd.Maintenance;
 import io.etcd.jetcd.impl.AbstractResponse;
 
 /**
- * StatusResponse returned by {@link Maintenance#statusMember(URI)} contains
+ * StatusResponse returned by {@link Maintenance#statusMember(String)} contains
  * a header, version, dbSize, current leader, raftIndex, and raftTerm.
  */
 public class StatusResponse extends AbstractResponse<io.etcd.jetcd.api.StatusResponse> {
@@ -33,6 +31,8 @@ public class StatusResponse extends AbstractResponse<io.etcd.jetcd.api.StatusRes
 
     /**
      * Returns the cluster protocol version used by the responding member.
+     *
+     * @return the version.
      */
     public String getVersion() {
         return getResponse().getVersion();
@@ -40,13 +40,17 @@ public class StatusResponse extends AbstractResponse<io.etcd.jetcd.api.StatusRes
 
     /**
      * Returns the size of the backend database, in bytes, of the responding member.
+     *
+     * @return the db sie.
      */
     public long getDbSize() {
         return getResponse().getDbSize();
     }
 
     /**
-     * Returns the the member ID which the responding member believes is the current leader.
+     * Returns the member ID which the responding member believes is the current leader.
+     *
+     * @return the leader.
      */
     public long getLeader() {
         return getResponse().getLeader();
@@ -54,6 +58,8 @@ public class StatusResponse extends AbstractResponse<io.etcd.jetcd.api.StatusRes
 
     /**
      * Returns the current raft index of the responding member.
+     *
+     * @return the raft index.
      */
     public long getRaftIndex() {
         return getResponse().getRaftIndex();
@@ -61,6 +67,8 @@ public class StatusResponse extends AbstractResponse<io.etcd.jetcd.api.StatusRes
 
     /**
      * Returns the current raft term of the responding member.
+     *
+     * @return the raft term.
      */
     public long getRaftTerm() {
         return getResponse().getRaftTerm();

jetcd-core/src/main/java/io/etcd/jetcd/op/TxnImpl.java

@@ -17,6 +17,7 @@
 package io.etcd.jetcd.op;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Function;
@@ -27,7 +28,6 @@ import io.etcd.jetcd.api.TxnRequest;
 import io.etcd.jetcd.kv.TxnResponse;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.collect.ImmutableList;
 
 /**
  * Build an etcd transaction.
@@ -60,7 +60,7 @@ public class TxnImpl implements Txn {
 
     @Override
     public TxnImpl If(Cmp... cmps) {
-        return If(ImmutableList.copyOf(cmps));
+        return If(Arrays.asList(cmps));
     }
 
     TxnImpl If(List<Cmp> cmps) {
@@ -77,7 +77,7 @@ public class TxnImpl implements Txn {
 
     @Override
     public TxnImpl Then(Op... ops) {
-        return Then(ImmutableList.copyOf(ops));
+        return Then(Arrays.asList(ops));
     }
 
     TxnImpl Then(List<Op> ops) {
@@ -93,7 +93,7 @@ public class TxnImpl implements Txn {
 
     @Override
     public TxnImpl Else(Op... ops) {
-        return Else(ImmutableList.copyOf(ops));
+        return Else(Arrays.asList(ops));
     }
 
     TxnImpl Else(List<Op> ops) {

jetcd-core/src/main/java/io/etcd/jetcd/options/CompactOption.java

@@ -17,15 +17,35 @@
 package io.etcd.jetcd.options;
 
 public final class CompactOption {
+    public static final CompactOption DEFAULT = builder().build();
 
-    public static final CompactOption DEFAULT = newBuilder().build();
+    private final boolean physical;
 
+    private CompactOption(boolean physical) {
+        this.physical = physical;
+    }
+
+    public boolean isPhysical() {
+        return physical;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    public static Builder builder() {
         return new Builder();
     }
 
-    public static class Builder {
-
+    public static final class Builder {
         private boolean physical = false;
 
         private Builder() {
@@ -49,14 +69,4 @@ public final class CompactOption {
             return new CompactOption(this.physical);
         }
     }
-
-    private final boolean physical;
-
-    private CompactOption(boolean physical) {
-        this.physical = physical;
-    }
-
-    public boolean isPhysical() {
-        return physical;
-    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/options/DeleteOption.java

@@ -21,21 +21,81 @@ import java.util.Optional;
 import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.KV;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 public final class DeleteOption {
+    public static final DeleteOption DEFAULT = builder().build();
 
-    public static final DeleteOption DEFAULT = newBuilder().build();
+    private final ByteSequence endKey;
+    private final boolean prevKV;
+    private final boolean prefix;
+    private final boolean autoRetry;
 
+    private DeleteOption(ByteSequence endKey, boolean prevKV, boolean prefix, final boolean autoRetry) {
+        this.endKey = endKey;
+        this.prevKV = prevKV;
+        this.prefix = prefix;
+        this.autoRetry = autoRetry;
+    }
+
+    public Optional<ByteSequence> getEndKey() {
+        return Optional.ofNullable(endKey);
+    }
+
+    /**
+     * Whether to get the previous key/value pairs before deleting them.
+     *
+     * @return true if get the previous key/value pairs before deleting them, otherwise false.
+     */
+    public boolean isPrevKV() {
+        return prevKV;
+    }
+
+    /**
+     * Whether to treat this deletion as deletion by prefix
+     *
+     * @return true if deletion by prefix.
+     */
+    public boolean isPrefix() {
+        return prefix;
+    }
+
+    /**
+     * Whether to treat a delete operation as idempotent from the point of view of automated retries.
+     * Note under failure scenarios this may mean a single delete is attempted more than once.
+     *
+     * @return true if automated retries should happen.
+     */
+    public boolean isAutoRetry() {
+        return autoRetry;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @return the builder
+     */
+    public static Builder builder() {
         return new Builder();
     }
 
-    public static class Builder {
-
-        private Optional<ByteSequence> endKey = Optional.empty();
+    public static final class Builder {
+        private ByteSequence endKey;
         private boolean prevKV = false;
         private boolean prefix = false;
+        private boolean autoRetry = false;
 
         private Builder() {
         }
@@ -59,7 +119,7 @@ public final class DeleteOption {
          * @return        builder
          */
         public Builder withRange(ByteSequence endKey) {
-            this.endKey = Optional.ofNullable(endKey);
+            this.endKey = endKey;
             return this;
         }
 
@@ -90,7 +150,7 @@ public final class DeleteOption {
          */
         @Deprecated
         public Builder withPrefix(ByteSequence prefix) {
-            checkNotNull(prefix, "prefix should not be null");
+            requireNonNull(prefix, "prefix should not be null");
             ByteSequence prefixEnd = OptionsUtil.prefixEndOf(prefix);
             this.withRange(prefixEnd);
             return this;
@@ -107,36 +167,23 @@ public final class DeleteOption {
             return this;
         }
 
+        /**
+         * When autoRetry is set, the delete operation is treated as idempotent from the point of view of automated retries.
+         * Note under some failure scenarios true may make a delete operation be attempted more than once, where
+         * a first attempt succeeded but its result did not reach the client; by default (autoRetry=false),
+         * the client won't retry since it is not safe to assume on such a failure the operation did not happen.
+         * Requesting withAutoRetry means the client is explicitly asking for retry nevertheless.
+         *
+         * @return builder
+         */
+        public Builder withAutoRetry() {
+            this.autoRetry = true;
+            return this;
+        }
+
         public DeleteOption build() {
-            return new DeleteOption(endKey, prevKV, prefix);
+            return new DeleteOption(endKey, prevKV, prefix, autoRetry);
         }
 
     }
-
-    private final Optional<ByteSequence> endKey;
-    private final boolean prevKV;
-    private final boolean prefix;
-
-    private DeleteOption(Optional<ByteSequence> endKey, boolean prevKV, boolean prefix) {
-        this.endKey = endKey;
-        this.prevKV = prevKV;
-        this.prefix = prefix;
-    }
-
-    public Optional<ByteSequence> getEndKey() {
-        return endKey;
-    }
-
-    /**
-     * Whether to get the previous key/value pairs before deleting them.
-     *
-     * @return true if get the previous key/value pairs before deleting them, otherwise false.
-     */
-    public boolean isPrevKV() {
-        return prevKV;
-    }
-
-    public boolean isPrefix() {
-        return prefix;
-    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/options/GetOption.java

@@ -20,26 +20,244 @@ import java.util.Optional;
 
 import io.etcd.jetcd.ByteSequence;
 import io.etcd.jetcd.KV;
+import io.etcd.jetcd.kv.GetResponse;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 /**
  * The option for get operation.
  */
 public final class GetOption {
+    public static final GetOption DEFAULT = builder().build();
 
-    public static final GetOption DEFAULT = newBuilder().build();
+    private final ByteSequence endKey;
+    private final long limit;
+    private final long revision;
+    private final SortOrder sortOrder;
+    private final SortTarget sortTarget;
+    private final boolean serializable;
+    private final boolean keysOnly;
+    private final boolean countOnly;
+    private final long minCreateRevision;
+    private final long maxCreateRevision;
+    private final long minModRevision;
+    private final long maxModRevision;
+    private final boolean prefix;
+
+    private GetOption(
+        ByteSequence endKey,
+        long limit,
+        long revision,
+        SortOrder sortOrder,
+        SortTarget sortTarget,
+        boolean serializable,
+        boolean keysOnly,
+        boolean countOnly,
+        long minCreateRevision,
+        long maxCreateRevision,
+        long minModRevision,
+        long maxModRevision,
+        boolean prefix) {
+
+        this.endKey = endKey;
+        this.limit = limit;
+        this.revision = revision;
+        this.sortOrder = sortOrder;
+        this.sortTarget = sortTarget;
+        this.serializable = serializable;
+        this.keysOnly = keysOnly;
+        this.countOnly = countOnly;
+        this.minCreateRevision = minCreateRevision;
+        this.maxCreateRevision = maxCreateRevision;
+        this.minModRevision = minModRevision;
+        this.maxModRevision = maxModRevision;
+        this.prefix = prefix;
+    }
 
     /**
-     * Create a builder to construct option for get operation.
+     * Get the maximum number of keys to return for a get request.
      *
-     * @return builder
+     * <p>
+     * Note this filter does not affect the count field in GetResponse.
+     * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+     * </p>
+     *
+     *
+     * @return the maximum number of keys to return.
      */
+    public long getLimit() {
+        return this.limit;
+    }
+
+    /**
+     * Get the end key for a range request
+     *
+     * @return the end key for a range request
+     */
+    public Optional<ByteSequence> getEndKey() {
+        return Optional.ofNullable(this.endKey);
+    }
+
+    /**
+     * Get the revision for the request
+     *
+     * @return the revision for the request
+     */
+    public long getRevision() {
+        return revision;
+    }
+
+    /**
+     * Get the sort order for the request
+     *
+     * @return the sort order for the request
+     */
+    public SortOrder getSortOrder() {
+        return sortOrder;
+    }
+
+    /**
+     * Get the sort field for the request
+     *
+     * @return the sort field for the request
+     */
+    public SortTarget getSortField() {
+        return sortTarget;
+    }
+
+    /**
+     * Return if the consistency level for this request is "serializable".
+     * Note serializable is a lower than default consistency, and implies
+     * the possibility of getting stale data.
+     *
+     * @return true if this request is only serializable consistency
+     */
+    public boolean isSerializable() {
+        return serializable;
+    }
+
+    /**
+     * True if this request should get only keys in a range and there is no
+     * need to retrieve the values.
+     *
+     * @return true if only get keys
+     */
+    public boolean isKeysOnly() {
+        return keysOnly;
+    }
+
+    /**
+     * True if this request should only populate the count of keys matching
+     * a range, and no other data.
+     *
+     * @return true if only get the count of keys
+     */
+    public boolean isCountOnly() {
+        return countOnly;
+    }
+
+    /**
+     * Only populate results for keys that match a
+     * minimum value for a created revision.
+     *
+     * <p>
+     * Note this filter does not affect the count field in GetResponse.
+     * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+     * For the same reason, it would be meaningless to mix setting a min create revision option
+     * with the count only option.
+     * </p>
+     *
+     * @return minimum created revision to match, or zero for any.
+     */
+    public long getMinCreateRevision() {
+        return this.minCreateRevision;
+    }
+
+    /**
+     * Only populate results for keys that match a
+     * maximum value for a created revision.
+     *
+     * <p>
+     * Note this filter does not affect the count field in GetResponse.
+     * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+     * For the same reason, it would be meaningless to mix setting a max create revision option
+     * with the count only option.
+     * </p>
+     *
+     * @return maximum created revision to match, or zero for any.
+     */
+    public long getMaxCreateRevision() {
+        return this.maxCreateRevision;
+    }
+
+    /**
+     * Only populate results for keys that match a
+     * minimum value for a modified revision.
+     *
+     * <p>
+     * Note this filter does not affect the count field in GetResponse.
+     * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+     * For the same reason, it would be meaningless to mix setting a min mod revision option
+     * with the count only option.
+     * </p>
+     *
+     * @return minimum modified revision to match, or zero for any.
+     */
+    public long getMinModRevision() {
+        return this.minModRevision;
+    }
+
+    /**
+     * Only populate results for keys that match a
+     * maximum value for a modified revision.
+     *
+     * <p>
+     * Note this filter does not affect the count field in GetResponse.
+     * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+     * For the same reason, it would be meaningless to mix setting a max mod revision option
+     * with the count only option.
+     * </p>
+     *
+     * @return maximum modified revision to match, or zero for any.
+     */
+    public long getMaxModRevision() {
+        return this.maxModRevision;
+    }
+
+    /**
+     * True if this Get request should do prefix match
+     *
+     * @return true if this Get request should do prefix match
+     */
+    public boolean isPrefix() {
+        return prefix;
+    }
+
+    public enum SortOrder {
+        NONE, ASCEND, DESCEND,
+    }
+
+    public enum SortTarget {
+        KEY, VERSION, CREATE, MOD, VALUE,
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    public static Builder builder() {
         return new Builder();
     }
 
-    public static class Builder {
+    public static final class Builder {
 
         private long limit = 0L;
         private long revision = 0L;
@@ -48,7 +266,7 @@ public final class GetOption {
         private boolean serializable = false;
         private boolean keysOnly = false;
         private boolean countOnly = false;
-        private Optional<ByteSequence> endKey = Optional.empty();
+        private ByteSequence endKey;
         private long minCreateRevision = 0L;
         private long maxCreateRevision = 0L;
         private long minModRevision = 0L;
@@ -61,6 +279,13 @@ public final class GetOption {
         /**
          * Limit the number of keys to return for a get request. By default is 0 - no limitation.
          *
+         * <p>
+         * Note this filter does not affect the count field in GetResponse.
+         * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+         * For the same reason, it would be meaningless to mix setting this option
+         * with the count only option.
+         * </p>
+         *
          * @param  limit the maximum number of keys to return for a get request.
          * @return       builder
          */
@@ -114,7 +339,9 @@ public final class GetOption {
          * <p>
          * Get requests are linearizable by
          * default. For better performance, a serializable get request is served locally without needing
-         * to reach consensus with other nodes in the cluster.
+         * to reach consensus with other nodes in the cluster. Note this is a tradeoff with strict
+         * consistency so it should be used with care in situations where reading stale
+         * is acceptable.
          *
          * @param  serializable is the get request a serializable get request.
          * @return              builder
@@ -164,7 +391,7 @@ public final class GetOption {
          * @return        builder
          */
         public Builder withRange(ByteSequence endKey) {
-            this.endKey = Optional.ofNullable(endKey);
+            this.endKey = endKey;
             return this;
         }
 
@@ -194,17 +421,24 @@ public final class GetOption {
          */
         @Deprecated
         public Builder withPrefix(ByteSequence prefix) {
-            checkNotNull(prefix, "prefix should not be null");
+            requireNonNull(prefix, "prefix should not be null");
             ByteSequence prefixEnd = OptionsUtil.prefixEndOf(prefix);
             this.withRange(prefixEnd);
             return this;
         }
 
         /**
-         * Limit returned keys to those with create revision greater than the provided value.
+         * Limit returned keys to those with create revision greater or equal than the provided value.
          * min_create_revision is the lower bound for returned key create revisions; all keys with
          * lesser create revisions will be filtered away.
          *
+         * <p>
+         * Note this filter does not affect the count field in GetResponse.
+         * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+         * For the same reason, it would be meaningless to mix setting this option
+         * with the count only option.
+         * </p>
+         *
          * @param  createRevision create revision
          * @return                builder
          */
@@ -214,10 +448,17 @@ public final class GetOption {
         }
 
         /**
-         * Limit returned keys to those with create revision less than the provided value.
+         * Limit returned keys to those with create revision less or equal than the provided value.
          * max_create_revision is the upper bound for returned key create revisions; all keys with
          * greater create revisions will be filtered away.
          *
+         * <p>
+         * Note this filter does not affect the count field in GetResponse.
+         * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+         * For the same reason, it would be meaningless to mix setting this option
+         * with the count only option.
+         * </p>
+         *
          * @param  createRevision create revision
          * @return                builder
          */
@@ -227,10 +468,17 @@ public final class GetOption {
         }
 
         /**
-         * Limit returned keys to those with mod revision greater than the provided value.
+         * Limit returned keys to those with mod revision greater or equal than the provided value.
          * min_mod_revision is the lower bound for returned key mod revisions; all keys with lesser mod
          * revisions will be filtered away.
          *
+         * <p>
+         * Note this filter does not affect the count field in GetResponse.
+         * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+         * For the same reason, it would be meaningless to mix setting this option
+         * with the count only option.
+         * </p>
+         *
          * @param  modRevision mod revision
          * @return             this builder instance
          */
@@ -240,10 +488,17 @@ public final class GetOption {
         }
 
         /**
-         * Limit returned keys to those with mod revision less than the provided value. max_mod_revision
+         * Limit returned keys to those with mod revision less or equal than the provided value. max_mod_revision
          * is the upper bound for returned key mod revisions; all keys with greater mod revisions will
          * be filtered away.
          *
+         * <p>
+         * Note this filter does not affect the count field in GetResponse.
+         * {@link GetResponse#getCount()} always counts the number of keys matched on a range, independent of filters.
+         * For the same reason, it would be meaningless to mix setting this option
+         * with the count only option.
+         * </p>
+         *
          * @param  modRevision mod revision
          * @return             this builder instance
          */
@@ -258,106 +513,21 @@ public final class GetOption {
          * @return the GetOption
          */
         public GetOption build() {
-            return new GetOption(endKey, limit, revision, sortOrder, sortTarget, serializable, keysOnly, countOnly,
-                minCreateRevision, maxCreateRevision, minModRevision, maxModRevision, prefix);
+            return new GetOption(
+                endKey,
+                limit,
+                revision,
+                sortOrder,
+                sortTarget,
+                serializable,
+                keysOnly,
+                countOnly,
+                minCreateRevision,
+                maxCreateRevision,
+                minModRevision,
+                maxModRevision,
+                prefix);
         }
 
     }
-
-    private final Optional<ByteSequence> endKey;
-    private final long limit;
-    private final long revision;
-    private final SortOrder sortOrder;
-    private final SortTarget sortTarget;
-    private final boolean serializable;
-    private final boolean keysOnly;
-    private final boolean countOnly;
-    private final long minCreateRevision;
-    private final long maxCreateRevision;
-    private final long minModRevision;
-    private final long maxModRevision;
-    private final boolean prefix;
-
-    private GetOption(Optional<ByteSequence> endKey, long limit, long revision, SortOrder sortOrder, SortTarget sortTarget,
-        boolean serializable, boolean keysOnly, boolean countOnly, long minCreateRevision, long maxCreateRevision,
-        long minModRevision, long maxModRevision, boolean prefix) {
-        this.endKey = endKey;
-        this.limit = limit;
-        this.revision = revision;
-        this.sortOrder = sortOrder;
-        this.sortTarget = sortTarget;
-        this.serializable = serializable;
-        this.keysOnly = keysOnly;
-        this.countOnly = countOnly;
-        this.minCreateRevision = minCreateRevision;
-        this.maxCreateRevision = maxCreateRevision;
-        this.minModRevision = minModRevision;
-        this.maxModRevision = maxModRevision;
-        this.prefix = prefix;
-    }
-
-    /**
-     * Get the maximum number of keys to return for a get request.
-     *
-     * @return the maximum number of keys to return.
-     */
-    public long getLimit() {
-        return this.limit;
-    }
-
-    public Optional<ByteSequence> getEndKey() {
-        return this.endKey;
-    }
-
-    public long getRevision() {
-        return revision;
-    }
-
-    public SortOrder getSortOrder() {
-        return sortOrder;
-    }
-
-    public SortTarget getSortField() {
-        return sortTarget;
-    }
-
-    public boolean isSerializable() {
-        return serializable;
-    }
-
-    public boolean isKeysOnly() {
-        return keysOnly;
-    }
-
-    public boolean isCountOnly() {
-        return countOnly;
-    }
-
-    public long getMinCreateRevision() {
-        return this.minCreateRevision;
-    }
-
-    public long getMaxCreateRevision() {
-        return this.maxCreateRevision;
-    }
-
-    public long getMinModRevision() {
-        return this.minModRevision;
-    }
-
-    public long getMaxModRevision() {
-        return this.maxModRevision;
-    }
-
-    public boolean isPrefix() {
-        return prefix;
-    }
-
-    public enum SortOrder {
-        NONE, ASCEND, DESCEND,
-    }
-
-    public enum SortTarget {
-        KEY, VERSION, CREATE, MOD, VALUE,
-    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/options/LeaseOption.java

@@ -17,14 +17,35 @@
 package io.etcd.jetcd.options;
 
 public class LeaseOption {
+    public static final LeaseOption DEFAULT = builder().build();
 
-    public static final LeaseOption DEFAULT = newBuilder().build();
+    private final boolean attachedKeys;
 
+    private LeaseOption(boolean attachedKeys) {
+        this.attachedKeys = attachedKeys;
+    }
+
+    public boolean isAttachedKeys() {
+        return attachedKeys;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    public static Builder builder() {
         return new Builder();
     }
 
-    public static class Builder {
+    public static final class Builder {
 
         private boolean attachedKeys;
 
@@ -46,14 +67,4 @@ public class LeaseOption {
         }
     }
 
-    private final boolean attachedKeys;
-
-    private LeaseOption(boolean attachedKeys) {
-        this.attachedKeys = attachedKeys;
-    }
-
-    public boolean isAttachedKeys() {
-        return attachedKeys;
-    }
-
 }

jetcd-core/src/main/java/io/etcd/jetcd/options/PutOption.java

@@ -22,20 +22,70 @@ import static com.google.common.base.Preconditions.checkArgument;
  * The options for put operation.
  */
 public final class PutOption {
+    public static final PutOption DEFAULT = builder().build();
 
-    public static final PutOption DEFAULT = newBuilder().build();
+    private final long leaseId;
+    private final boolean prevKV;
+    private final boolean autoRetry;
 
+    private PutOption(long leaseId, boolean prevKV, boolean autoRetry) {
+        this.leaseId = leaseId;
+        this.prevKV = prevKV;
+        this.autoRetry = autoRetry;
+    }
+
+    /**
+     * Get the lease id.
+     *
+     * @return the lease id
+     */
+    public long getLeaseId() {
+        return this.leaseId;
+    }
+
+    /**
+     * Get the previous KV.
+     *
+     * @return the prevKV
+     */
+    public boolean getPrevKV() {
+        return this.prevKV;
+    }
+
+    /**
+     * Whether to treat a put operation as idempotent from the point of view of automated retries.
+     * Note under failure scenarios this may mean a single put executes more than once.
+     *
+     * @return true if automated retries should happen.
+     */
+    public boolean isAutoRetry() {
+        return autoRetry;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    public static Builder builder() {
         return new Builder();
     }
 
     /**
      * Builder to construct a put option.
      */
-    public static class Builder {
+    public static final class Builder {
 
         private long leaseId = 0L;
         private boolean prevKV = false;
+        private boolean autoRetry = false;
 
         private Builder() {
         }
@@ -63,40 +113,29 @@ public final class PutOption {
             return this;
         }
 
+        /**
+         * When autoRetry is set, treat this put as idempotent from the point of view of automated retries.
+         * Note under some failure scenarios autoRetry=true may make a put operation execute more than once, where
+         * a first attempt succeeded but its result did not reach the client; by default (autoRetry=false),
+         * the client won't retry since it is not safe to assume on such a failure that the operation did not happen
+         * in the server.
+         * Requesting withAutoRetry means the client is explicitly asking for retry nevertheless.
+         *
+         * @return builder
+         */
+        public Builder withAutoRetry() {
+            this.autoRetry = true;
+            return this;
+        }
+
         /**
          * build the put option.
          *
          * @return the put option
          */
         public PutOption build() {
-            return new PutOption(this.leaseId, this.prevKV);
+            return new PutOption(this.leaseId, this.prevKV, this.autoRetry);
         }
 
     }
-
-    private final long leaseId;
-    private final boolean prevKV;
-
-    private PutOption(long leaseId, boolean prevKV) {
-        this.leaseId = leaseId;
-        this.prevKV = prevKV;
-    }
-
-    /**
-     * Get the lease id.
-     *
-     * @return the lease id
-     */
-    public long getLeaseId() {
-        return this.leaseId;
-    }
-
-    /**
-     * Get the previous KV.
-     *
-     * @return the prevKV
-     */
-    public boolean getPrevKV() {
-        return this.prevKV;
-    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/options/TxnOption.java

@@ -0,0 +1,54 @@
+package io.etcd.jetcd.options;
+
+public final class TxnOption {
+    public static final TxnOption DEFAULT = builder().build();
+
+    private final boolean autoRetry;
+
+    private TxnOption(final boolean autoRetry) {
+        this.autoRetry = autoRetry;
+    }
+
+    /**
+     * Whether to treat a txn operation as idempotent from the point of view of automated retries.
+     *
+     * @return true if automated retries should happen.
+     */
+    public boolean isAutoRetry() {
+        return autoRetry;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @return the builder
+     */
+    public static TxnOption.Builder builder() {
+        return new TxnOption.Builder();
+    }
+
+    public static final class Builder {
+        private boolean autoRetry = false;
+
+        private Builder() {
+        }
+
+        /**
+         * When autoRetry is set, the txn operation is treated as idempotent from the point of view of automated retries.
+         * Note under some failure scenarios true may make a txn operation be attempted and/or execute more than once, where
+         * a first attempt executed but its result status did not reach the client; by default (autoRetry=false),
+         * the client won't retry since it is not safe to assume on such a failure the operation did not happen.
+         * Requesting withAutoRetry means the client is explicitly asking for retry nevertheless.
+         *
+         * @return builder
+         */
+        public Builder withAutoRetry() {
+            this.autoRetry = true;
+            return this;
+        }
+
+        public TxnOption build() {
+            return new TxnOption(autoRetry);
+        }
+    }
+}

jetcd-core/src/main/java/io/etcd/jetcd/options/WatchOption.java

@@ -20,30 +20,135 @@ import java.util.Optional;
 
 import io.etcd.jetcd.ByteSequence;
 
-import static com.google.common.base.Preconditions.checkNotNull;
+import static java.util.Objects.requireNonNull;
 
 /**
  * The option for watch operation.
  */
 public final class WatchOption {
+    public static final WatchOption DEFAULT = builder().build();
 
-    public static final WatchOption DEFAULT = newBuilder().build();
+    private final ByteSequence endKey;
+    private final long revision;
+    private final boolean prevKV;
+    private final boolean progressNotify;
+    private final boolean createdNotify;
+    private final boolean noPut;
+    private final boolean noDelete;
+    private final boolean requireLeader;
+    private final boolean prefix;
+
+    private WatchOption(ByteSequence endKey, long revision, boolean prevKV, boolean progressNotify, boolean createdNotify,
+        boolean noPut, boolean noDelete, boolean requireLeader, boolean prefix) {
+        this.endKey = endKey;
+        this.revision = revision;
+        this.prevKV = prevKV;
+        this.progressNotify = progressNotify;
+        this.createdNotify = createdNotify;
+        this.noPut = noPut;
+        this.noDelete = noDelete;
+        this.requireLeader = requireLeader;
+        this.prefix = prefix;
+    }
+
+    public Optional<ByteSequence> getEndKey() {
+        return Optional.ofNullable(this.endKey);
+    }
 
     /**
-     * Create a builder to construct option for watch operation.
+     * Returns the revision to watch from.
      *
-     * @return builder
+     * @return the revision.
      */
+    public long getRevision() {
+        return revision;
+    }
+
+    /**
+     * Whether created watcher gets the previous KV before the event happens.
+     *
+     * @return if true, watcher receives the previous KV before the event happens.
+     */
+    public boolean isPrevKV() {
+        return prevKV;
+    }
+
+    /**
+     * Whether watcher server send periodic progress updates.
+     *
+     * @return if true, watcher server should send periodic progress updates.
+     */
+    public boolean isProgressNotify() {
+        return progressNotify;
+    }
+
+    /**
+     * Whether watcher server send watch create event.
+     *
+     * @return if true, watcher server should send watch create event.
+     */
+    public boolean isCreatedNotify() {
+        return createdNotify;
+    }
+
+    /**
+     * Whether filter put event in server side.
+     *
+     * @return if true, filter put event in server side
+     */
+    public boolean isNoPut() {
+        return noPut;
+    }
+
+    /**
+     * Whether filter delete event in server side.
+     *
+     * @return if true, filter delete event in server side
+     */
+    public boolean isNoDelete() {
+        return noDelete;
+    }
+
+    /**
+     * If true, when creating the watch streaming stub, use the REQUIRED_LEADER Metadata annotation,
+     * which ensures the stream will error out if quorum is lost by
+     * the server the stream is connected to. This will make the watch fail with an error
+     * and finish.
+     * Without this option, a watch running against a server that is out of quorum
+     * simply goes silent.
+     *
+     * @return if true, use REQUIRE_LEADER metadata annotation for watch streams
+     */
+    public boolean withRequireLeader() {
+        return requireLeader;
+    }
+
+    public boolean isPrefix() {
+        return prefix;
+    }
+
+    /**
+     * Returns the builder.
+     *
+     * @deprecated use {@link #builder()}
+     * @return     the builder
+     */
+    @SuppressWarnings("InlineMeSuggester")
+    @Deprecated
     public static Builder newBuilder() {
+        return builder();
+    }
+
+    public static Builder builder() {
         return new Builder();
     }
 
-    public static class Builder {
-
+    public static final class Builder {
         private long revision = 0L;
-        private Optional<ByteSequence> endKey = Optional.empty();
+        private ByteSequence endKey;
         private boolean prevKV = false;
         private boolean progressNotify = false;
+        private boolean createNotify = false;
         private boolean noPut = false;
         private boolean noDelete = false;
         private boolean requireLeader = false;
@@ -87,7 +192,7 @@ public final class WatchOption {
          * @return        builder
          */
         public Builder withRange(ByteSequence endKey) {
-            this.endKey = Optional.ofNullable(endKey);
+            this.endKey = endKey;
             return this;
         }
 
@@ -115,6 +220,17 @@ public final class WatchOption {
             return this;
         }
 
+        /**
+         * When createNotify is set, the watch server sends event when watch is created.
+         *
+         * @param  createNotify configure the watcher to receive watch create event.
+         * @return              builder
+         */
+        public Builder withCreateNotify(boolean createNotify) {
+            this.createNotify = createNotify;
+            return this;
+        }
+
         /**
          * filter out put event in server side.
          *
@@ -157,7 +273,7 @@ public final class WatchOption {
          */
         @Deprecated
         public Builder withPrefix(ByteSequence prefix) {
-            checkNotNull(prefix, "prefix should not be null");
+            requireNonNull(prefix, "prefix should not be null");
             ByteSequence prefixEnd = OptionsUtil.prefixEndOf(prefix);
             this.withRange(prefixEnd);
             return this;
@@ -179,94 +295,9 @@ public final class WatchOption {
         }
 
         public WatchOption build() {
-            return new WatchOption(endKey, revision, prevKV, progressNotify, noPut, noDelete, requireLeader, prefix);
+            return new WatchOption(endKey, revision, prevKV, progressNotify, createNotify, noPut, noDelete, requireLeader,
+                prefix);
         }
 
     }
-
-    private final Optional<ByteSequence> endKey;
-    private final long revision;
-    private final boolean prevKV;
-    private final boolean progressNotify;
-    private final boolean noPut;
-    private final boolean noDelete;
-    private final boolean requireLeader;
-    private final boolean prefix;
-
-    private WatchOption(Optional<ByteSequence> endKey, long revision, boolean prevKV, boolean progressNotify, boolean noPut,
-        boolean noDelete, boolean requireLeader, boolean prefix) {
-        this.endKey = endKey;
-        this.revision = revision;
-        this.prevKV = prevKV;
-        this.progressNotify = progressNotify;
-        this.noPut = noPut;
-        this.noDelete = noDelete;
-        this.requireLeader = requireLeader;
-        this.prefix = prefix;
-    }
-
-    public Optional<ByteSequence> getEndKey() {
-        return this.endKey;
-    }
-
-    /**
-     * Returns the revision to watch from.
-     */
-    public long getRevision() {
-        return revision;
-    }
-
-    /**
-     * Whether created watcher gets the previous KV before the event happens.
-     *
-     * @return if true, watcher receives the previous KV before the event happens.
-     */
-    public boolean isPrevKV() {
-        return prevKV;
-    }
-
-    /**
-     * Whether watcher server send periodic progress updates.
-     *
-     * @return if true, watcher server should send periodic progress updates.
-     */
-    public boolean isProgressNotify() {
-        return progressNotify;
-    }
-
-    /**
-     * Whether filter put event in server side.
-     *
-     * @return if true, filter put event in server side
-     */
-    public boolean isNoPut() {
-        return noPut;
-    }
-
-    /**
-     * Whether filter delete event in server side.
-     *
-     * @return if true, filter delete event in server side
-     */
-    public boolean isNoDelete() {
-        return noDelete;
-    }
-
-    /**
-     * If true, when creating the watch streaming stub, use the REQUIRED_LEADER Metadata annotation,
-     * which ensures the stream will error out if quorum is lost by
-     * the server the stream is connected to. This will make the watch fail with an error
-     * and finish.
-     * Without this option, a watch running against a server that is out of quorum
-     * simply goes silent.
-     *
-     * @return if true, use REQUIRE_LEADER metadata annotation for watch streams
-     */
-    public boolean withRequireLeader() {
-        return requireLeader;
-    }
-
-    public boolean isPrefix() {
-        return prefix;
-    }
 }

jetcd-core/src/main/java/io/etcd/jetcd/resolver/AbstractNameResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 The jetcd authors
+ * Copyright 2016-2023 The jetcd authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,7 @@ package io.etcd.jetcd.resolver;
 
 import java.net.URI;
 import java.util.List;
-import java.util.concurrent.Executor;
+import java.util.Objects;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -29,8 +29,6 @@ import io.grpc.Attributes;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.NameResolver;
 import io.grpc.Status;
-import io.grpc.internal.GrpcUtil;
-import io.grpc.internal.SharedResourceHolder;
 
 import com.google.common.base.Preconditions;
 
@@ -46,7 +44,6 @@ public abstract class AbstractNameResolver extends NameResolver {
     private volatile boolean shutdown;
     private volatile boolean resolving;
 
-    private Executor executor;
     private Listener listener;
 
     public AbstractNameResolver(URI targetUri) {
@@ -68,8 +65,7 @@ public abstract class AbstractNameResolver extends NameResolver {
     public void start(Listener listener) {
         synchronized (lock) {
             Preconditions.checkState(this.listener == null, "already started");
-            this.executor = SharedResourceHolder.get(GrpcUtil.SHARED_CHANNEL_EXECUTOR);
-            this.listener = Preconditions.checkNotNull(listener, "listener");
+            this.listener = Objects.requireNonNull(listener, "listener");
             resolve();
         }
     }
@@ -85,21 +81,13 @@ public abstract class AbstractNameResolver extends NameResolver {
             return;
         }
         shutdown = true;
-
-        synchronized (lock) {
-            if (executor != null) {
-                executor = SharedResourceHolder.release(GrpcUtil.SHARED_CHANNEL_EXECUTOR, executor);
-            }
-        }
     }
 
     private void resolve() {
         if (resolving || shutdown) {
             return;
         }
-        synchronized (lock) {
-            executor.execute(this::doResolve);
-        }
+        doResolve();
     }
 
     private void doResolve() {
@@ -123,7 +111,7 @@ public abstract class AbstractNameResolver extends NameResolver {
             savedListener.onAddresses(groups, Attributes.EMPTY);
 
         } catch (Exception e) {
-            LOGGER.warn("Error wile getting list of servers", e);
+            LOGGER.warn("Error while getting list of servers", e);
             savedListener.onError(Status.NOT_FOUND);
         } finally {
             resolving = false;