Java Flight Recorder (JFR) records events inside the JVM so you can investigate application behavior over time. It helps connect symptoms—such as a failed request or a slow background job—to exceptions, thread contention, I/O delays, CPU activity, and garbage collection.
A recording is especially useful when application logs show only part of the story. You can examine the events around the failure and compare their timestamps and threads instead of investigating each symptom in isolation.
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<?xml version="1.0" encoding="UTF-8"?>
<configuration version="2.0" label="Exceptions and Diagnostics (Java 21)" description="Captures all Java exceptions, errors, socket/file I/O, locks, GC, and CPU profiling with low allocation noise" provider="Custom">
<!-- EXCEPTIONS & ERRORS (Full Throwable + Stack Trace Capture) -->
<event name="jdk.JavaExceptionThrow">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.JavaErrorThrow">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.ExceptionStatistics">
<setting name="enabled">true</setting>
<setting name="period">1000 ms</setting>
</event>
<!-- NETWORK & FILE I/O (JDBC Socket Drops, Vaulting, Slow Reads/Writes) -->
<event name="jdk.SocketRead">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.SocketWrite">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.FileRead">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.FileWrite">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.FileForce">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<!-- CPU & EXECUTION PROFILING -->
<event name="jdk.ExecutionSample">
<setting name="enabled">true</setting>
<setting name="period">20 ms</setting>
</event>
<event name="jdk.NativeMethodSample">
<setting name="enabled">true</setting>
<setting name="period">20 ms</setting>
</event>
<event name="jdk.CPULoad">
<setting name="enabled">true</setting>
<setting name="period">1000 ms</setting>
</event>
<event name="jdk.ThreadCPULoad">
<setting name="enabled">true</setting>
<setting name="period">10 s</setting>
</event>
<!-- THREADING, CONTENTION & JAVA 21 VIRTUAL THREADS -->
<event name="jdk.JavaMonitorEnter">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.JavaMonitorWait">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.ThreadPark">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">10 ms</setting>
</event>
<event name="jdk.ThreadStart">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.ThreadEnd">
<setting name="enabled">true</setting>
</event>
<event name="jdk.JavaThreadStatistics">
<setting name="enabled">true</setting>
<setting name="period">1000 ms</setting>
</event>
<!-- Java 21 specific: Virtual Thread pinning & submit failures -->
<event name="jdk.VirtualThreadPinned">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="threshold">20 ms</setting>
</event>
<event name="jdk.VirtualThreadSubmitFailed">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<!-- GARBAGE COLLECTION & MEMORY (Low Overhead, TLAB Churn Disabled) -->
<event name="jdk.GarbageCollection">
<setting name="enabled">true</setting>
<setting name="threshold">0 ms</setting>
</event>
<event name="jdk.GCPhasePause">
<setting name="enabled">true</setting>
<setting name="threshold">0 ms</setting>
</event>
<event name="jdk.GCHeapSummary">
<setting name="enabled">true</setting>
<setting name="period">everyChunk</setting>
</event>
<event name="jdk.MetaspaceSummary">
<setting name="enabled">true</setting>
<setting name="period">everyChunk</setting>
</event>
<event name="jdk.AllocationRequiringGC">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
</event>
<!-- Java 16+ rate-throttled allocation sample (150/s keeps chunk growth tiny; set 0/s to disable completely) -->
<event name="jdk.ObjectAllocationSample">
<setting name="enabled">true</setting>
<setting name="stackTrace">true</setting>
<setting name="throttle">150/s</setting>
</event>
<!-- Keep legacy unthrottled TLAB events explicitly off -->
<event name="jdk.ObjectAllocationInNewTLAB">
<setting name="enabled">false</setting>
<setting name="stackTrace">true</setting>
</event>
<event name="jdk.ObjectAllocationOutsideTLAB">
<setting name="enabled">false</setting>
<setting name="stackTrace">true</setting>
</event>
<!-- JVM METADATA & ENVIRONMENT (Written at the start of every 256M chunk)-->
<event name="jdk.JVMInformation">
<setting name="enabled">true</setting>
<setting name="period">beginChunk</setting>
</event>
<event name="jdk.OSInformation">
<setting name="enabled">true</setting>
<setting name="period">beginChunk</setting>
</event>
<event name="jdk.InitialSystemProperty">
<setting name="enabled">true</setting>
<setting name="period">beginChunk</setting>
</event>
<event name="jdk.ActiveSetting">
<setting name="enabled">true</setting>
<setting name="period">beginChunk</setting>
</event>
<event name="jdk.ActiveRecording">
<setting name="enabled">true</setting>
<setting name="period">beginChunk</setting>
</event>
</configuration>