When Weblogic Server (WLS) loads more than ~400 EJBs, the HotSpot VM throws an OutOfMemoryError exception. This occurs even though there appears to be lots of memory available; in our scenario, there was over 460 mb of memory available
based on a call to Runtime.getRuntime().freeMemory(). Loading large number
of EJBs was possible with previous versions of the VM.

The HotSpot VM was throwing the OutOfMemoryError when trying to allocate
PermGeneration space. It appears that the HotSpot VM has different sections
of memory. The permanent generation section (used for classes, methods,
symbols ??) has an initial size of 1 mb and a max size of 32 mb.

Fortunately, this limit can be raised at runtime using the

        java -server -XX:MaxPermSize=65536K

command line argument. The above command raises the MaxPermSize to 64 mb. With this limit, we were able to load additional ejbs.

However, the -XX options are not supported, and ISVs/Customers are wary about using XX options.

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Note that currently, increasing the MaxPermSize only delays the failure.

neal.gafter@Eng 2001-05-22