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Can One pressure generation of the JVM crash log file?

How do i pressure or generate a JVM core dump with an Java application server or perhaps in general?

Problem(Abstract): To identify the issues associated with hang or poor performance of customer programs running on WebSphere Application Server Community Edition, customers could be needed to create the different dumps and send these to IBM Support for diagnosis.

This technote describes how you can generate needed dumps when WebSphere Application Server Community Edition is running being an operating-system service. This technote is applicable to IBM Java SDK 1.5. and IBM Java SDK 1.6.

Cause: When customer programs experience hang or poor performance with WebSphere Application Server Community Edition on IBM Java SDK 1.5. or IBM Java SDK 1.6., and also the server is running being an operating-system service, the related command/spend window from the server process isn't open to customers. Consequently, user signals cannot be sent in the keyboard to trigger dumps.

Solving the issue: Once the JVM process command window can be obtained, producing dumps is easy the following:

Home windows: When the JVM setting is set up to trigger the dumps at user signal, press CRTL+Break around the command window to create the dumps.

Linux: When the JVM setting is set up to create the dumps at user signal, press CTRL+\ around the spend window.

AIX: When the JVM setting is set up to create the dumps at user signal, press CTRL+\ around the spend window.

Note: To be able to generate java core dump, system core dump, heap dump along with a snap dump at user signal, the dump agents should be set up through JVM options the following:

-Xdump:java+heap+system+snap:events=user

For additional info on how you can configure dump agents, visit using -Xdump.

However, if WebSphere Application Server Community Edition is running being an operating-system service, the command window might not be available. This situation will even arise when JVM process is began with javaw.exe on home windows.

Within the preceding conditions, user is needed to obtain the corresponding process-id from the JVM process and employ operating-system vendor provided or IBM provided tools to create the dumps by using the below steps.

Home windows: WinDbg obtainable from Microsoft Dev tools site to create system core dumps. Make use of the following command in the WinDbg console to create the machine core dump:

dump /f <dumpfile> 

Where dumpfile includes your directory path and also the title from the system core dump file. Make certain that /f choice is used rather than /ma. The /f creates full dump while /ma creates small dump. Only full dumps are supported using the jextract tool provided with IBM Java SDK 1.5./1.6..

SendSignal utility for Home windows. With this, the JVM should be setup to create the dumps on user signals. To create the java core dump, heap dump, system core dump along with a snap dump at user signal, the next option should be provided to JVM at startup:

-Xdump:java+heap+system+snap:events=user 

Note: The SendSignal utility may be used to generate all kinds of dumps while WinDbg generate only system core dumps.

Linux and AIX: The signal for Linux and AIX is SIGQUIT. Make use of the command to transmit the consumer signal to trigger the different dumps:

kill -3 <PID>  

With this, JVM should be setup to create the dumps on user signal. To create the java core dump, heap dump, system core dump along with a snap sump at user signal, the next option should be provided to JVM at startup.

-Xdump:java+heap+system+snap:events=user 

Note: System core dump files must processed while using jextract oral appliance the output should be send to IBM support. The jextract in the same JVM that experienced the issue should be employed to process the machine core dump:

<JAVA_HOME>/jre/bin/jextract <dumpfile>   

Where dumpfile may be the filename from the system core dump.

This can create a zip file .zip. The zip file must be delivered to IBM support.