JVM Thread Dump Analysis Part 1

JVM & Thread Dump Fundamentals:


Thread Dump : Thread Dump is a snapshot at given time which provides complete listing of all threads created in java.

Thread Dump Generation Tools :

1) OS Native Command (kill -3<pid>)
2) JDK jstack utility
3) Java visual VM
4) Oracle Weblogic Admin Console

1 ) ps -ef  | grep java - this will list all java processes
2) jstack pid | more


If JVM is healthy then we can use JDK jstack or java visual JVM, else we can use OS Native command.OS native command always better to avoid further performance problems.

In weblogic under servers -monitoring - threads

hogging threads- A thread executing same requesting more than 5 sec. - This option is available in web logic console.

How to Analyse Thread dump

1) First verify healthy and non healthy threads  - for ex stuck thread might be unhealthy thread - we need to identity pattern instead of analyzing all threads.

2) Verify Heap Size

3)