I'm running my project on JBoss 4.2. Hibernate is used outside project ear (for some reason I don't know). I've been investigating classloader memory leaks (as described in article http://blogs.sun.com/fkieviet/entry/classloader_leaks_the_dreaded_java) - the problem is that project classes are not garbage collected after undeployment.
I've found that EnumType Hibernate class has a static field:
private static Map<Class, Object[]> enumValues
which holds references to my enum types, which all have reference to the classloader of most of my classes. As Hibernate is outside ear, EnumType class is not garbage collected after project undeployment and because of that static field all my classes are not garbage collected as well, which is a memory leak.
Is that a bug in that class ? Should that Map hold weak references or sth ?
Any ideas how I can deal with that problem ?

It's a bug;
the field must be java.util.WeakHashMap

>>I'm running my project on JBoss 4.2. Hibernate is used outside project ear (for some reason I don't know)
it's in the lib directory of jboss w/ the deployer MBean

To deal w/ the issuel

in some class of yours add
static{
java.lang.reflect.Field f = EnumType.class.getDeclaredField("enumValues");
f.setAccessible(true);
Map m = (Map) f.get(null);
if (m instanceof HashMap){
Map weak = new WeakHashMap(m);
f.set(null, weak);
}
}

or recompile hibernate replace new HashMap w/ new WeakHashMap
----
edit: upon reflection i recalled simple WeakHashMap will not do since the value has reference to the class, thus the it will not be cleared
Instead of WeakHashMap, use something like that (entryset(), values()), containsValue(Object) will not work though)
new WeakHashMap(){
public Object get(Object key){
WeakReference w = (WeakReference) super.get(key):
if (w==null) return null;
return w.get();
}
public Object put(Object key, Object value){
WeakReference w = (WeakReference) super.put(key, new WeakReference(value)):
if (w==null) return null;
return w.get();
}
}