Message6044

Spent a little more time looking at the heap dump and here are some places that I think are pinning the classloader:
 (1) ShutdownCloser (nested class PySystemState$PySystemStateCloser$ShutdownCloser) is registered as a shutdown hook, which as I pointed out previously, will pin the classloader.
 (2) Some elements of the com.google.common.base.internal.Finalizer thread appear to reference the containing classloader (contextClassLoader and inheritedAccessControlContext member variables) - bug #92 in guava (http://code.google.com/p/guava-libraries/issues/detail?id=92) mentions this as well (see comment #6). Apparently this was discovered in 2008 but still not fixed. 

There are a whole bunch more references to the finalizer thread, but I am hoping that those will go away once the other references to the webapp classloader are cleared.