java-debug-playground

NOT YET IMPLEMENTED

📚 Learning and exploring debugging and profiling tools in Java, the Java toolchain and the Java ecosystem.

Instructions

Follow these instructions to build and run the demo program:

1. Use Java 17
2. Build and run the program:

   • ./gradlew run

Wish List

Things I wish for!

• Implement some examples using Java Flight Recording
  • As a reference, use https://github.com/dgroomes/wiremock-playground/blob/ecf7f4b7490a28f2df6ce01489d52e881d30cd76/docs/CONTRIBUTING.md

Notes

Build a distribution: ./gradlew installDist

Run with args: JAVA_OPTS="-XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints" ./build/install/java-debug-playground/bin/java-debug-playground 30

List Java processes (that can be recorded using JFR?): jcmd

Start a JFR for some running Java process jcmd 3891 JFR.start

Dump the the JFR recording to file (the Java process must still be running! If it's terminated, you're too late!) jcmd 3891 JFR.dump name=1 filename=1.jfr

To get a flight recording from the start of the program's execution through the finish, add the options -XX:StartFlightRecording,dumponexit=true

• So, in full: JAVA_OPTS="-XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints -XX:StartFlightRecording,dumponexit=true" ./build/install/java-debug-playground/bin/java-debug-playground 30