# Semantic conventions for JVM metrics **Status**: [Mixed][DocumentStatus] This document describes semantic conventions for JVM metrics in OpenTelemetry. - [JVM memory](#jvm-memory) - [Metric: `jvm.memory.used`](#metric-jvmmemoryused) - [Metric: `jvm.memory.committed`](#metric-jvmmemorycommitted) - [Metric: `jvm.memory.limit`](#metric-jvmmemorylimit) - [Metric: `jvm.memory.used_after_last_gc`](#metric-jvmmemoryused_after_last_gc) - [JVM garbage collection](#jvm-garbage-collection) - [Metric: `jvm.gc.duration`](#metric-jvmgcduration) - [JVM threads](#jvm-threads) - [Metric: `jvm.thread.count`](#metric-jvmthreadcount) - [JVM classes](#jvm-classes) - [Metric: `jvm.class.loaded`](#metric-jvmclassloaded) - [Metric: `jvm.class.unloaded`](#metric-jvmclassunloaded) - [Metric: `jvm.class.count`](#metric-jvmclasscount) - [JVM CPU](#jvm-cpu) - [Metric: `jvm.cpu.time`](#metric-jvmcputime) - [Metric: `jvm.cpu.count`](#metric-jvmcpucount) - [Metric: `jvm.cpu.recent_utilization`](#metric-jvmcpurecent_utilization) - [Development](#development) - [Metric: `jvm.memory.init`](#metric-jvmmemoryinit) - [Metric: `jvm.system.cpu.utilization`](#metric-jvmsystemcpuutilization) - [Metric: `jvm.system.cpu.load_1m`](#metric-jvmsystemcpuload_1m) - [Metric: `jvm.buffer.memory.used`](#metric-jvmbuffermemoryused) - [Metric: `jvm.buffer.memory.limit`](#metric-jvmbuffermemorylimit) - [Metric: `jvm.buffer.count`](#metric-jvmbuffercount) ## JVM memory **Status**: [Stable][DocumentStatus] **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.memory.*` ### Metric: `jvm.memory.used` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.memory.used` | UpDownCounter | `By` | Measure of memory used. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.memory.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | `Recommended` |  | | [`jvm.memory.type`](/docs/attributes-registry/jvm.md) | string | The type of memory. | `heap`; `non_heap` | `Recommended` |  | **[1] `jvm.memory.pool.name`:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). --- `jvm.memory.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `heap` | Heap memory. |  | | `non_heap` | Non-heap memory |  | ### Metric: `jvm.memory.committed` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.memory.committed` | UpDownCounter | `By` | Measure of memory committed. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.memory.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | `Recommended` |  | | [`jvm.memory.type`](/docs/attributes-registry/jvm.md) | string | The type of memory. | `heap`; `non_heap` | `Recommended` |  | **[1] `jvm.memory.pool.name`:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). --- `jvm.memory.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `heap` | Heap memory. |  | | `non_heap` | Non-heap memory |  | ### Metric: `jvm.memory.limit` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.memory.limit` | UpDownCounter | `By` | Measure of max obtainable memory. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.memory.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | `Recommended` |  | | [`jvm.memory.type`](/docs/attributes-registry/jvm.md) | string | The type of memory. | `heap`; `non_heap` | `Recommended` |  | **[1] `jvm.memory.pool.name`:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). --- `jvm.memory.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `heap` | Heap memory. |  | | `non_heap` | Non-heap memory |  | ### Metric: `jvm.memory.used_after_last_gc` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getCollectionUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getCollectionUsage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.memory.used_after_last_gc` | UpDownCounter | `By` | Measure of memory used, as measured after the most recent garbage collection event on this pool. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.memory.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | `Recommended` |  | | [`jvm.memory.type`](/docs/attributes-registry/jvm.md) | string | The type of memory. | `heap`; `non_heap` | `Recommended` |  | **[1] `jvm.memory.pool.name`:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). --- `jvm.memory.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `heap` | Heap memory. |  | | `non_heap` | Non-heap memory |  | ## JVM garbage collection **Status**: [Stable][DocumentStatus] **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.gc.*` ### Metric: `jvm.gc.duration` This metric is [recommended][MetricRecommended]. This metric is obtained by subscribing to [`GarbageCollectionNotificationInfo`](https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/GarbageCollectionNotificationInfo.html) events provided by [`GarbageCollectorMXBean`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/GarbageCollectorMXBean.html). The duration value is obtained from [`GcInfo`](https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/GcInfo.html#getDuration--) This metric SHOULD be specified with [`ExplicitBucketBoundaries`](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.43.0/specification/metrics/api.md#instrument-advisory-parameters) of `[ 0.01, 0.1, 1, 10 ]`. | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.gc.duration` | Histogram | `s` | Duration of JVM garbage collection actions. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.gc.action`](/docs/attributes-registry/jvm.md) | string | Name of the garbage collector action. [1] | `end of minor GC`; `end of major GC` | `Recommended` |  | | [`jvm.gc.name`](/docs/attributes-registry/jvm.md) | string | Name of the garbage collector. [2] | `G1 Young Generation`; `G1 Old Generation` | `Recommended` |  | **[1] `jvm.gc.action`:** Garbage collector action is generally obtained via [GarbageCollectionNotificationInfo#getGcAction()](https://docs.oracle.com/en/java/javase/11/docs/api/jdk.management/com/sun/management/GarbageCollectionNotificationInfo.html#getGcAction()). **[2] `jvm.gc.name`:** Garbage collector name is generally obtained via [GarbageCollectionNotificationInfo#getGcName()](https://docs.oracle.com/en/java/javase/11/docs/api/jdk.management/com/sun/management/GarbageCollectionNotificationInfo.html#getGcName()). ## JVM threads **Status**: [Stable][DocumentStatus] **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.thread.*` ### Metric: `jvm.thread.count` This metric is [recommended][MetricRecommended]. This metric is obtained from a combination of * [`ThreadMXBean#getAllThreadIds()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ThreadMXBean.html#getAllThreadIds--) * [`ThreadMXBean#getThreadInfo()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ThreadMXBean.html#getThreadInfo-long:A-) * [`ThreadInfo#getThreadState()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ThreadInfo.html#getThreadState--) * [`ThreadInfo#isDaemon()`](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/ThreadInfo.html#isDaemon()) (requires Java 9+) Note that this is the number of platform threads (as opposed to virtual threads). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.thread.count` | UpDownCounter | `{thread}` | Number of executing platform threads. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.thread.daemon`](/docs/attributes-registry/jvm.md) | boolean | Whether the thread is daemon or not. | | `Recommended` |  | | [`jvm.thread.state`](/docs/attributes-registry/jvm.md) | string | State of the thread. | `runnable`; `blocked` | `Recommended` |  | --- `jvm.thread.state` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `blocked` | A thread that is blocked waiting for a monitor lock is in this state. |  | | `new` | A thread that has not yet started is in this state. |  | | `runnable` | A thread executing in the Java virtual machine is in this state. |  | | `terminated` | A thread that has exited is in this state. |  | | `timed_waiting` | A thread that is waiting for another thread to perform an action for up to a specified waiting time is in this state. |  | | `waiting` | A thread that is waiting indefinitely for another thread to perform a particular action is in this state. |  | ## JVM classes **Status**: [Stable][DocumentStatus] **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.class.*` ### Metric: `jvm.class.loaded` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getTotalLoadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getTotalLoadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.class.loaded` | Counter | `{class}` | Number of classes loaded since JVM start. |  | ### Metric: `jvm.class.unloaded` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getUnloadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getUnloadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.class.unloaded` | Counter | `{class}` | Number of classes unloaded since JVM start. |  | ### Metric: `jvm.class.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getLoadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getLoadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.class.count` | UpDownCounter | `{class}` | Number of classes currently loaded. |  | ## JVM CPU **Status**: [Stable][DocumentStatus] **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.cpu.*` ### Metric: `jvm.cpu.time` This metric is [recommended][MetricRecommended]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getProcessCpuTime()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuTime()) on HotSpot and [`com.ibm.lang.management.OperatingSystemMXBean#getProcessCpuTime()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html#getProcessCpuTime--) on OpenJ9. | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.cpu.time` | Counter | `s` | CPU time used by the process as reported by the JVM. |  | ### Metric: `jvm.cpu.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`Runtime#availableProcessors()`](https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#availableProcessors--). Note that this is always an integer value (i.e. fractional or millicores are not represented). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.cpu.count` | UpDownCounter | `{cpu}` | Number of processors available to the Java virtual machine. |  | ### Metric: `jvm.cpu.recent_utilization` This metric is [recommended][MetricRecommended]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getProcessCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuLoad()) on HotSpot and [`com.ibm.lang.management.OperatingSystemMXBean#getProcessCpuLoad()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html#getProcessCpuLoad--) on OpenJ9. Note that the JVM does not provide a definition of what "recent" means. | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.cpu.recent_utilization` | Gauge | `1` | Recent CPU utilization for the process as reported by the JVM. [1] |  | **[1]:** The value range is [0.0,1.0]. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuLoad()). ## Development **Status**: [Development][DocumentStatus] **Description:** In-development Java Virtual Machine (JVM) metrics captured under `jvm.` ### Metric: `jvm.memory.init` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.memory.init` | UpDownCounter | `By` | Measure of initial memory requested. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.memory.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | `Recommended` |  | | [`jvm.memory.type`](/docs/attributes-registry/jvm.md) | string | The type of memory. | `heap`; `non_heap` | `Recommended` |  | **[1] `jvm.memory.pool.name`:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). --- `jvm.memory.type` has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used. | Value | Description | Stability | |---|---|---| | `heap` | Heap memory. |  | | `non_heap` | Non-heap memory |  | ### Metric: `jvm.system.cpu.utilization` This metric is [Opt-In][MetricOptIn]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getSystemCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getSystemCpuLoad()) on Java version 8..13, [`com.sun.management.OperatingSystemMXBean#getCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()) on Java version 14+, and [`com.ibm.lang.management.OperatingSystemMXBean#getSystemCpuLoad()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html) on OpenJ9. | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.system.cpu.utilization` | Gauge | `1` | Recent CPU utilization for the whole system as reported by the JVM. [1] |  | **[1]:** The value range is [0.0,1.0]. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()). ### Metric: `jvm.system.cpu.load_1m` This metric is [Opt-In][MetricOptIn]. This metric is obtained from [`OperatingSystemMXBean#getSystemLoadAverage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.system.cpu.load_1m` | Gauge | `{run_queue_item}` | Average CPU load of the whole system for the last minute as reported by the JVM. [1] |  | **[1]:** The value range is [0,n], where n is the number of CPU cores - or a negative number if the value is not available. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/java.management/java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage()). ### Metric: `jvm.buffer.memory.used` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getMemoryUsed()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getMemoryUsed--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.buffer.memory.used` | UpDownCounter | `By` | Measure of memory used by buffers. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.buffer.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the buffer pool. [1] | `mapped`; `direct` | `Recommended` |  | **[1] `jvm.buffer.pool.name`:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). ### Metric: `jvm.buffer.memory.limit` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getTotalCapacity()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getTotalCapacity--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.buffer.memory.limit` | UpDownCounter | `By` | Measure of total memory capacity of buffers. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.buffer.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the buffer pool. [1] | `mapped`; `direct` | `Recommended` |  | **[1] `jvm.buffer.pool.name`:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). ### Metric: `jvm.buffer.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getCount--). | Name | Instrument Type | Unit (UCUM) | Description | Stability | | -------- | --------------- | ----------- | -------------- | --------- | | `jvm.buffer.count` | UpDownCounter | `{buffer}` | Number of buffers in the pool. |  | | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`jvm.buffer.pool.name`](/docs/attributes-registry/jvm.md) | string | Name of the buffer pool. [1] | `mapped`; `direct` | `Recommended` |  | **[1] `jvm.buffer.pool.name`:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). [DocumentStatus]: https://opentelemetry.io/docs/specs/otel/document-status [MetricOptIn]: /docs/general/metric-requirement-level.md#opt-in [MetricRecommended]: /docs/general/metric-requirement-level.md#recommended