The GrafLoader (possibly the GrafParser) contains a memory leak and reusing the same loader to load multiple graph objects will eventually cause an application to run out of heap space.
The memory leak was in the GrafParser class due to a design flaw in the IAnnoationSpace API. Removed code left over from the days of "annotation sets", when the AnnotationSet class attempted to record all instances of the annotations in the set. This caused the leak since annotations were never removed from the sets when a graph was destroyed.
The fix will be in Subversion soon and this will be closed when 1.2 is released.
The fix is now in Subversion and 1.2.0-SNAPSHOT on Maven. Ticket will be closed when 1.2.0 is released.