weblogic, jdk1.5 memory issues

I am using weblogic 9.2, jdk1.5, and oracle 10g for my application and getting some memory issues

I have a report servlet for 4 different kinds of reports of mi开发者_C百科llions of db records

Now my problem is this, that when I run the report one at a time (single user), no memory issue occurs say

when report was executing memory was 775 mb when report finish executing memory was 836 mb

Now

sooner the concurrent users request for the reports the memory leakage starts

even after the end of each report only few memory is reclaimed say

when reports was executing memory was 33 mb when reports finish executing memory was 86 mb

it stays on 86mb forever until next request gets java.lang.OutOfMemoryError

I have called System.gc after the end of each report execution but it only gets down to a 86mb

~ I am instantiating a report object inside servlet's post method for each request

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What is your Heap set to with Xmx and Xms

Looks like you are creating a lot of temporary objects when running your report which reside in the Eden space (within Young space). These can be tuned by changing values of Xms with respect to Xmx.

Maybe when concurrent users hitting your app are having resource contention to underlying database or whatever else.

I suggest you profile your application with VisualVM or YourKit. Also read Troubleshooting Memory Leaks