Java memory leak

[nocturn]

I 'inherited' a java app at work that now appears to have a memory leak.
I do not have Java experience, what would be the best way to track down the leak, are there any good tools that can help?

Thanks.

[HungSquirrel]

Java IS a memory leak. :P

[nocturn]

Java IS a memory leak. :P
Tell me about it...

If I get my way (which is very possible), most of the code will gradually be replaced with something in perl or python.

[defkewl]

Tell me about it...

If I get my way (which is very possible), most of the code will gradually be replaced with something in perl or python.
Try these : http://www.quest.com/jprobe/debugger.asp

[nocturn]

Thanks for the tips

I tried the profiler, but beause it is a class, called from a JSP file, it does not run inside it.

I cannot figure out what it is doing. The app is supposed to http-transfer a file (40 MB in my test). It uses 310 MB to do this, and after the class quits, the java process is till using 200 MB (as opposed to 8 before it started).

I hate java :-(

[vague-]

It uses 310 MB to do this, and after the class quits, the java process is till using 200 MB (as opposed to 8 before it started).


I cannot guarantee this, as I am not 100% sure, but I do not think that is a memory leak. Instead, in a similar manner to other VMs such as Perl, the VM is probably keeping a large proportion of the memory previously allocated for future allocations - which saves asking the operating system for it repeatedly. Many VMs can exhibit behaviour such as this when performing a high memory task off the bat. Googling for a solution is probably a good idea. Though not JVM specific (read: I have not tried them), you could try performing the memory hogging task in another process - thus, this process would close and free the memory associated with it. I think there are solutions within the JVM itself.

Of course, I could be wrong and do just have some random straggling reference to a large chunk of the memory you parsed and so the GC will not get rid of it.