Episode 53 “Analyzing Crashed JVMs” [IJN]

Posted on April 4, 2026

The Java tool jcmd (“j command”) sends diagnostic commands to the JVM, which will react by supplying the desired information: from finalizer queues to heap and thread dumps, from GC insights to virtual thread scheduler statistics. At the moment, this requires a running JVM, but once candidate JEP 528 is adopted, a lot of that information can be seamlessly extracted from a crashed JVM’s core dump, allowing easy post-mortem analysis.

Links:

jcmd documentation: https://docs.oracle.com/en/java/javase/26/docs/specs/man/jcmd.html
JEP 528: https://openjdk.org/jeps/528

Make sure to also check the Duke’s Corner podcast on dev.java.

Additional resources

Inside.java : News and views from members of the Java team at Oracle
Dev.java : The Destination for Java Developers
OpenJDK
Oracle Java

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