18

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!

Saar
  • 1,753
  • 6
  • 20
  • 32

4 Answers4

12

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
Codeguard
  • 7,787
  • 2
  • 38
  • 41
  • 1
    I understand this is an old thread but - When I try to open a DMP file created through Task Manager (64-bit java process/application) I get the following error: "c:\Temp\ApplicationName.DMP is not a valid core dump!" I have tried the visualvm instead of jvisualbv, but it doesn't have a "VM Coredumps" option showing. – Brian Booth Sep 12 '19 at 14:02
  • Hi @BrianBooth, i generated my `.dmp` file from the Task Manager, by right-clicking on `java.exe`, then `Create dump file`. Then, i followed the Steps described by Codeguard for `jvisualvm`, and it works perfectly. Did you create a dumpfile from a `java` process? I reproduce your error, by creating a dump file for a `Chrome` process, and when i try to add the item under `jvisualvm - VM Coredumps`, it tells me `chrome.DMP is not a valid core dump!` – jumping_monkey Dec 03 '19 at 03:32
7

jvisualvm can be used to load a dump and then analyze it

EDIT:

This comes in the JDK redist...

Aaron McIver
  • 24,527
  • 5
  • 59
  • 88
  • 3
    That tool can be used to view a Windows Crash Dump file (.dmp)? I don't see a way to do this. – Bryan May 18 '11 at 16:01
  • @Bryan Java heap dump; you can dump within the tool; providing a point in time of the state of the JVM you were monitoring. – Aaron McIver May 18 '11 at 16:21
5

There's a Java Heap Analysis Tool

Boris Pavlović
  • 63,078
  • 28
  • 122
  • 148
0

NetBeans 6.9.1 can load .hprof file (Profile -> Load Heap Dump). Then, for example, you can search for the biggest object and see it's internals.

Andrey Lebedenko
  • 1,850
  • 17
  • 24