JVM Guides & How-tos

Practical, example-first guides for working with the JVM: reading thread and heap dumps, tuning JVM flags, and analyzing garbage collection - real commands, not just theory.

• JVM Flags: The Practical Tuning Guide

  Understand and tune JVM flags: heap sizing (-Xmx/-Xms), default -XX settings, GC and JFR flags, how to inspect and mutate flags with jinfo and jcmd.

• Heap Dump Analysis: From OutOfMemoryError to Root Cause

  Step-by-step heap dump analysis: capture with jmap/jcmd, enable -XX:+HeapDumpOnOutOfMemoryError, open in Eclipse MAT, and use OQL to find leaks.

• Thread Dump Analysis: Diagnose Hangs and Deadlocks

  Read Java thread dumps to find hangs, deadlocks and blocked threads: capture with jstack/jcmd, identify thread states, and spot the culprit stack.