We got our hand on a heapDump last week and we found that most of the memory where occupy by a large map hold by "java.io.DeleteOnExitHook" that is referencing temporary files created by Magnolia (about 200 000 references)

This problem is referenced in sereral threads (http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6664633, http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4872014, http://bugs.java.com/bugdatabase/view_bug.do?bug_id=4809375)

We are going to correct this problem by removing the deleteOnExit call on the temp file.
Find the usages and create tickets in corresponding modules (currently used in activation, dam, CTS...).