Comments on: Java Memory Leaks

By: loolek

loolek — Tue, 24 Feb 2009 13:07:09 +0000

This is a good tool too ->

http://www.alphaworks.ibm.com/tech/heapanalyzer

–
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However, a large number of electrons were terribly inconvenienced.”

By: Nirmal

Nirmal — Tue, 14 Oct 2008 12:32:12 +0000

Hi,

I am using jmap on Linux (JVM is 1.5.0_15-b04).

I use the following command to take the heap dump:
jmap -heap:format=b

This creates a heap dump file in my current directory as “heap.bin”.

I then copied this heap.bin from Linux to windows using Winscp.

But from windows when I open this file in SAP Memory Analyzer(with open snapshot) it gives me the following error:
org.eclipse.core.runtime.CoreException: Text editor does not have a document provider
at org.eclipse.ui.texteditor.AbstractTextEditor.doSetInput(AbstractTextEditor.java:3928)
at org.eclipse.ui.texteditor.StatusTextEditor.doSetInput(StatusTextEditor.java:190)
at org.eclipse.ui.texteditor.AbstractDecoratedTextEditor.doSetInput(AbstractDecoratedTextEditor.java:1225)
at org.eclipse.ui.editors.text.TextEditor.doSetInput(TextEditor.java:168)
at org.eclipse.ui.texteditor.AbstractTextEditor$19.run(AbstractTextEditor.java:2994)
at

I even renamed the dump file to “heap.hprof” as in the sample snapshots of SAP memory Analyzer the filenames are: “HeapDumpSample.hprof”

Please help me in opening the heap dump file from jmap in SAP Memory Analyzer.

Where did I make a mistake?

Nirmal…..

By: charlie

charlie — Mon, 13 Oct 2008 18:36:53 +0000

I suspect it is either you don’t have permission to write to the current directory, or you aren’t running jmap as the owner of the process.

By: John P. Anderson

John P. Anderson — Mon, 13 Oct 2008 12:25:01 +0000

I tried running your command (jmap -heap:format=b $pid) but all I get is the following:

Attaching to process ID 6535, please wait…
Debugger attached successfully.
Server compiler detected.
JVM version is 1.5.0_15-b04
heap.bin (Permission denied)

Anyone got any idea of what is happening here?

By: charlie

charlie — Tue, 17 Jun 2008 14:39:19 +0000

UPDATE:

The SAP Memory Analyzer is now an Eclipse project

By: joychester

joychester — Sun, 18 May 2008 13:01:39 +0000

Charlie,
You can try this way to use Jconsole 6 remotely to detect your application memory leak, even your application is under JDK5, not JDK6. (That means your remote dasktop or laptop is under JDK6)I am using this way very well
(BTW,Jconsole in JDK5 is not good at all.)

For further analysis(personally speaking, I perfered to use Netbean heap walker) we should use other tools to support. if application is using JDK6, everything is good, you can extract memory heap snapshot banary file using “Mbean” tab. if application is under JDK5, then you need other tools to support.
Here we just talk about the open source solution.

—Joychester, Performance engineer

By: Charlie

Charlie — Tue, 13 May 2008 14:34:47 +0000

As you point out, jconsole can be good for detection, but once you’ve identified a memory leak exists, you have to move to other tools to find root cause.

In general, the java tools are much improved in Java 6, but a lot of people aren’t on Java 6 in production systems. So I’m stuck with Java 5 and the problems that jmap has in some older revisions (at least updates 11 and 12 are known to have the issue described above).

By: joychester

joychester — Mon, 12 May 2008 16:22:30 +0000

here is my practice based on my daily testing work, not that hard if you make it systemiclly:
1.jconsole is a very good tool for detecting java memory leak issue at first.
2.narrow down the test cases or senarios to find which part may cause the problem
3.also i love jmap to get heap dump snapshot to get deep analysis after we are clear we have an issue on memory.
4. use some tool to read the binary heap dump file if necessary
–Joychester,performance testing engineer