Some tweaks to improve gradle cacheability (#1030)

auto-exporters/auto-exporters.gradle

@@ -40,7 +40,7 @@ dependencies {
     shadowInclude project(path: ':auto-exporters:opentelemetry-auto-exporter-zipkin', configuration: 'shadow')
 }
 
-
+jar.enabled = false
 shadowJar {
     configurations = [project.configurations.shadowInclude]
 

auto-exporters/jaeger/jaeger.gradle

@@ -14,6 +14,7 @@ dependencies {
   implementation group: 'io.grpc', name: 'grpc-netty-shaded', version: '1.24.0'
 }
 
+jar.enabled = false
 shadowJar {
   archiveClassifier = ''
 }

auto-exporters/logging/logging.gradle

@@ -11,6 +11,7 @@ dependencies {
   compileOnly deps.opentelemetrySdkAutoConfig
 }
 
+jar.enabled = false
 shadowJar {
   archiveClassifier = ''
 }

auto-exporters/otlp/otlp.gradle

@@ -14,6 +14,7 @@ dependencies {
   implementation group: 'io.grpc', name: 'grpc-netty-shaded', version: '1.24.0'
 }
 
+jar.enabled = false
 shadowJar {
   archiveClassifier = ''
 }

auto-exporters/zipkin/zipkin.gradle

@@ -12,6 +12,7 @@ dependencies {
   compileOnly deps.opentelemetrySdkAutoConfig
 }
 
+jar.enabled = false
 shadowJar {
   archiveClassifier = ''
 }

gradle/java.gradle

@@ -36,14 +36,6 @@ java {
   withSourcesJar()
 }
 
-sourceSets {
-  main {
-    java {
-      srcDir 'src/main/java'
-    }
-  }
-}
-
 tasks.withType(JavaCompile) {
   options.compilerArgs.addAll(['--release', project.ext.release.majorVersion])
 }
@@ -289,3 +281,8 @@ tasks.withType(Test).configureEach {
     junitXml.outputPerTestCase = true
   }
 }
+
+tasks.withType(AbstractArchiveTask) {
+  preserveFileTimestamps = false
+  reproducibleFileOrder = true
+}