Thread Dump Analysis Tool / Method
When the Java application is hanging, you don't even know the use case that is leading to this and want to investigate, I understand that thread dumps can be useful.
But how can we easily derive useful data from the thread dumps to find where the problem is? The server application that I've been working with produces very long thread dumps, because it is an EJB architecture and thread dumps contains many container threads that I'm not sure I should be looking at (i.e. threads that are not running my application code, but JBoss's code).
Yesterday I tried the Thread Dump Analyzer tool. The tool is definitely better than looking at the raw thread dumps in a text editor, because you can filter out threads that you're not interested in, see the thread list, click on a thread to see its details, compare thread dumps to find long running threads, etc.
But there's still too much data to analyse - almost 300 threads. I don't know of any criteria that I could use to filter out all the JBoss threads, in which I'm not interested. I'm not sure if I should be looking at threads that are currently in "runnable" state only or if "waiting on condition" and "in Object.wait" are also important.
What's the approach that you would normally follow and tools that you would in general use?
Answer
I know this is an old question but I just wrote a tool to help make long thread dumps more readable.
Java Thread Dump Analysis Tool
This tool groups threads together which have the same stack trace and allows you to only show threads which are in particular states (e.g. RUNNABLE or BLOCKED).
This makes it a bit quicker to find the interesting threads amongst the tens or hundreds of JBoss threads which spend most of their time waiting for work at the same place in the code and therefore all have the same stack trace.