Dump file analysis of Java process?

Question

If I take dump, using Windbg, of Java process running on Windows

Can I analyze (easly?) the Java heap, objects, and threads?

Just like I could do with SOS for .Net process?

Otherwise - how can I offline debug a problem happening on production systems?

Thanks!

Answer 1

Windows minidumps (.dmp) can be used with these utilities:

1. jvisualvm utility from JDK can get you both thread dump and heap dump

   • Open jvisualvm
   • In the Applications pane, find VM Coredumps
   • Right-click it
   • Select Add VM Coredump...
   • Browse to your .dmp minidump file
   • Press OK
   • Right-click the new item under VM Coredumps
   • Select Thread Dump
   • Repeat for Heap Dump

2. jstack utility from JDK can show Java stack from Windows minidumps (.dmp)

   Here's a batch script for that:

   :: Shows java stack from Windows minidumps
   :: Argument %1: Path to minidump
   @ECHO OFF
   
   SET JDK_PATH=C:\Program Files\Java\jdk1.8.0_181\bin
   
   "%JDK_PATH%\jstack.exe" "%JDK_PATH%\java" "%~1"
   PAUSE
   

3. jmap utility from JDK can convert Windows minidump (.dmp) to java heap dump (.hprof)

   Here's a batch script for that:

   :: Converts Windows minidump to Java heap dump (.hprof)
   :: Argument %1: Path to minidump
   @ECHO OFF
   
   SET JDK_PATH=C:\Program Files\Java\jdk1.8.0_181\bin
   
   "%JDK_PATH%\jmap.exe" -F -dump:format=b,file="%~dpn1.hprof" "%JDK_PATH%\java" "%~1"
   PAUSE