[jira] Updated: (BEANUTILS-291) Circular Reference on WeakHashMap

["Clebert Rezende Suconic (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/BEANUTILS-291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Clebert Rezende Suconic updated BEANUTILS-291:
----------------------------------------------

    Attachment: ThreadIsolationAndTestImprovement.patch

I *believe* there is a thread isolation problem on PropertyUtilsBean. I was actually having few test hickups.. *maybe* caused by that.

I have changed FastHashMap a little bit to allow creations and constructions on a sub method, and I created a WeakHashMap that will use those methods.

I also changed PropertyUtilsBean to use the "new" WeakHashMap.

I have deleted that WeakHashMap inner class and used the new one created.


And I have also changed the testcase a little bit. It is now checking for releases on SoftReferences, as they are not aways released. 

For the MemoryLeakTestCase, it would be good if you could change mvn or whatever starts the test, to run it with less memory (-Xmx25M for instance). This way this test would run in less than 10 seconds.

With those fixes I'm attaching now I got a 100% testsuite pass.


(Please review the patch before applying it)

> 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
>
>         Attachments: BEANUTILS-291-FixMemoryLeaks-v2.patch, memoryLeakTests-new.zip, PropertyUtilsBean.java, ThreadIsolationAndTestImprovement.patch
>
>
> Clebert Suconic wrote on the dev@commons 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)
> org.jboss.web.tomcat.service.WebAppClassLoader@16334564
> !--- sun.reflect.DelegatingClassLoader@27651708
> !--- !--- class sun.reflect.GeneratedConstructorAccessor38
> !--- !--- !--- [Ljava.lang.Object;@10800875
> !--- !--- !--- !--- java.util.Vector@838806
> !--- !--- !--- !--- !--- sun.reflect.DelegatingClassLoader@27651708
> !--- !--- !--- !--- !--- !--- class sun.reflect.GeneratedConstructorAccessor38
> !--- !--- !--- !--- !--- !--- !--- class java.lang.Class
> !--- !--- !--- !--- !--- !--- !--- !--- org.apache.commons.beanutils.converters.ClassConverter@22616909
> !--- !--- !--- !--- !--- !--- !--- !--- !--- org.apache.commons.beanutils.converters.ArrayConverter@18888821
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- org.apache.commons.beanutils.converters.ConverterFacade@13619754
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- java.util.HashMap$Entry@32434103
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- [Ljava.util.HashMap$Entry;@28236766
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- java.util.HashMap@14997495
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- org.apache.commons.beanutils.ConvertUtilsBean@2016953
> !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- !--- org.apache.commons.beanutils.BeanUtilsBean@30487951
> !--- !--- !--- !--- !--- !--- !--- !--- !-- -!--- !--- !--- !--- !--- !--- !---FieldReference private java.lang.Object java.util.WeakHashMap$Entry.value=java.util.WeakHashMap$Entry@23775534 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.

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