I have been investigating WeakHashMaps on BeanUtils 1.8 as part of a
investigation on this:
http://jira.jboss.com/jira/browse/JBAS-2299
(Which is not actually an issue with JBAS, but an issue when using
BeanUtils as part of the classPath).
There is a circular reference on the WeakHashMap, The WeakHashMap will
have the ClassLoader as the key, and it will have a reference back to
the Key from one of the Reflection objects. This doesn't work! (Please..
no discussions about this point.. if you don't believe me, do some
testing with simple stuff before discussing this and come back to me
only after that)
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Detail
I don't know if I'm preaching to the choir, but just in case this is new
information to someone... you should aways keep Reflection referenced as
SoftReferences (if you really have to). Reflection is aways a new object
so a WeakReference is too weak.
On JBossSerialization I have solved this using an interesting way. I
called it PersistentReference. I'm using SoftReferences, and keeping the
information to recreate it case the SoftReference is cleared:
http://fisheye.jboss.org/browse/JBoss/jboss-serialization/src/org/jboss/serial/references/PersistentReference.java?r=1.3
And also... you guys should write a testcase to validate if the Caching
is being cleared. (I don't know if you have one).
http://anonsvn.jboss.org/repos/jbossserialization/trunk/tests/org/jboss/serial/memory/MemoryLeakTestCase.java
You don't need to use the jboss-profiler API for this.. just create a
WeakReference to a new ClassLoader, and validate if it was released at
the end after some exercizing some code on this caching. You will
probably need to fill your memory almost to 100% on the test as
SoftReference are only gone when the memory is low.
Clebert Suconic
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