Problem

An error like the following occurs. It could be any module, the Quartz Scheduler is an example.

Exception in thread "DefaultQuartzScheduler_QuartzSchedulerThread" java.lang.OutOfMemoryError: PermGen space
Exception in thread "http-80-Processor1" java.lang.OutOfMemoryError: PermGen space
Exception in thread "http-80-Processor2" java.lang.OutOfMemoryError: PermGen space
Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1" java.lang.OutOfMemoryError: PermGen space

Cause

If you get the error message: java.lang.OutOfMemoryError: PermGen space this means that you have exceeded Java's fixed block for loading class files. Permanent Generation Memory, unlike Java heap space, is the memory allocation for the classes themselves as opposed to the objects created. The addition of more plugins contributes to more consumption of PermGen space. The error occurs when enough classes are invoked.

Resolution

This is only relevant for Confluence 5.7 and below as Java 8 manages PermGen automatically.

To avoid this in the future follow the steps detailed in the guide How to fix out of memory errors by increasing available memory. Find the instructions on how to increase the Permanent Generation Space. Make sure to change -XX:MaxPermSize rather than the Heap Space Parameters.