application activity, but CPU is 90% busy by JAVA

[lzlatin]

The application runs under Web Sphere. After it has finished, “Web Sphere monitoring and tuning” shows no application activity, but CPU is 90% busy by JAVA. We cannot define which process occupies it. If we run the application again it will be stuck. How can we define which process occupies CPU?
Thanks in advance.

[kjkoster]

Dear lzlatin,

I'm not sure what you mean by 'the application'. Do you mean the application you deployed in WAS or the application to load test the WAS server?

You can take thread dumps to resolve issues with threads that keep running when you don't expect them to. Here is a discussion how to find why a Java app is only using a single processor (http://java-monitor.com/forum/showthread.php?t=317) and here is a discussion on analyzing hanging Tomcat processes using thread dumps (http://java-monitor.com/forum/showthread.php?t=616). While neither discussion tells you precisely what to do, they both show how to work with thread dumps. I hope you find some information in there to get you started at least.

In your case, you will have to take thread dumps and search for threads that are running. Then check your code to find what these threads are doing.

Let us know what you find.

Kees Jan

[lzlatin]

Thanks a lot. Thread dumps helped us.

[kjkoster]

Dear lzlatin,

Could you elaborate on what the problem was and how you solved it?

Kees Jan