Circular Reference on WeakHashMap
---------------------------------
Key: BEANUTILS-291
URL: https://issues.apache.org/jira/browse/BEANUTILS-291
Project: Commons BeanUtils
Issue Type: Bug
Components: Bean / Property Utils
Affects Versions: 1.8.0-BETA
Reporter: Niall Pemberton
Fix For: 1.8.0
Clebert Suconic wrote on the [EMAIL PROTECTED] list ....
(see http://tinyurl.com/2a9gan)
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)
[EMAIL PROTECTED]
!--- [EMAIL PROTECTED]
!--- !--- class sun.reflect.GeneratedConstructorAccessor38
!--- !--- !--- [Ljava.lang.Object;@10800875
!--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- class sun.reflect.GeneratedConstructorAccessor38
!--- !--- !--- !--- !--- !--- !--- class java.lang.Class
!--- !--- !--- !--- !--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- [EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !---
[Ljava.util.HashMap$Entry;@28236766
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- [EMAIL
PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- [EMAIL
PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !---
[EMAIL PROTECTED]
!--- !--- !--- !--- !--- !--- !--- !--- !-- -!--- !--- !--- !--- !--- !---
!---FieldReference private java.lang.Object [EMAIL PROTECTED] 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.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
