This is the jira that links to the java issue that explains why we can't
use loadClass, the bug is still active, so we have to keep
Class.forName<br><a href="https://issues.jboss.org/browse/JBRULES-1553" target="_blank">https://issues.jboss.org/browse/JBRULES-1553</a><br>
<a href="http://bugs.sun.com/bugdatabase/view_bug.do;jsessionid=2a9a78e4393c5e678a2c80f90c1?bug_id=6434149" target="_blank">http://bugs.sun.com/bugdatabase/view_bug.do;jsessionid=2a9a78e4393c5e678a2c80f90c1?bug_id=6434149</a><br>
<br>Mark<br><div class="gmail_quote">On Thu, Nov 17, 2011 at 5:53 PM, Mauricio Salatino <span dir="ltr"><<a href="mailto:salaboy@gmail.com">salaboy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Just a small update:<br>
If I compile core and compiler with tests I'm just getting the<br>
following failing tests in compiler:<br>
Failed tests:<br>
testMonitorResourceChangeEvents(org.drools.agent.KnowledgeAgentDisposeTest)<br>
testDispose(org.drools.agent.KnowledgeAgentDisposeTest)<br>
<br>
Tests in error:<br>
testAccumulateMultipleFunctionsJava(org.drools.integrationtests.AccumulateTest)<br>
testAccumulateMultipleFunctionsMVEL(org.drools.integrationtests.AccumulateTest)<br>
testAccumulateMinMax(org.drools.integrationtests.AccumulateTest)<br>
testAccumulateCE(org.drools.integrationtests.AccumulateTest)<br>
<br>
I think that the knowledge agents problem is not related with the<br>
Class.forName() change, but all the failing test inside the<br>
AccumulateTest fails because the following line inside<br>
ClassFieldAccessorCache:<br>
124: return this.classLoader.loadClass( className );<br>
<br>
Debugging, I didn't find the reason of the following stack trace:<br>
org.drools.RuntimeDroolsException: Unable to resolve class '[Ljava.lang.Object;'<br>
at org.drools.base.ClassFieldAccessorCache.getClass(ClassFieldAccessorCache.java:126)<br>
at org.drools.base.ClassFieldAccessorCache.getClassObjectType(ClassFieldAccessorCache.java:48)<br>
at org.drools.base.ClassFieldAccessorStore.getClassObjectType(ClassFieldAccessorStore.java:285)<br>
at org.drools.base.ClassFieldAccessorStore.getClassObjectType(ClassFieldAccessorStore.java:271)<br>
at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:291)<br>
at org.drools.rule.builder.PatternBuilder.build(PatternBuilder.java:130)<br>
at org.drools.rule.builder.GroupElementBuilder.build(GroupElementBuilder.java:65)<br>
at org.drools.rule.builder.RuleBuilder.build(RuleBuilder.java:80)<br>
at org.drools.compiler.PackageBuilder.addRule(PackageBuilder.java:2302)<br>
at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:823)<br>
at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:405)<br>
at org.drools.compiler.PackageBuilder.addKnowledgeResource(PackageBuilder.java:587)<br>
at org.drools.builder.impl.KnowledgeBuilderImpl.add(KnowledgeBuilderImpl.java:37)<br>
at org.drools.integrationtests.AccumulateTest.loadKnowledgeBase(AccumulateTest.java:111)<br>
at org.drools.integrationtests.AccumulateTest.execTestAccumulateMultipleFunctions(AccumulateTest.java:1656)<br>
at org.drools.integrationtests.AccumulateTest.testAccumulateMultipleFunctionsJava(AccumulateTest.java:940)<br>
<br>
Because the community hudson is down I can't check if it's a local<br>
problem or a master one.<br>
<br>
Cheers<br>
<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
On Wed, Nov 16, 2011 at 5:48 PM, Mauricio Salatino <<a href="mailto:salaboy@gmail.com">salaboy@gmail.com</a>> wrote:<br>
> We really need to analyze the difference and understand what is<br>
> happening under the hood.. because if not strange things can happen.<br>
> I will run the tests locally to see if I see something wrong.<br>
><br>
> Cheers<br>
><br>
> On Wed, Nov 16, 2011 at 5:46 PM, Mark Proctor <<a href="mailto:mproctor@codehaus.org">mproctor@codehaus.org</a>> wrote:<br>
>> We original used classLoader.loadClass but then there was wierd bug with<br>
>> dynamic rules that wouldn't work, related to arrays. Switching to<br>
>> Class.forName avoided that bug. But I don't remember the exact details, it<br>
>> was several years ago now.<br>
>><br>
>> Mark<br>
>><br>
>> On Wed, Nov 16, 2011 at 5:50 PM, Mauricio Salatino <<a href="mailto:salaboy@gmail.com">salaboy@gmail.com</a>><br>
>> wrote:<br>
>>><br>
>>> Based on more tests and reading some articles about OSGI we (Professor<br>
>>> dotty and I) have found that<br>
>>> the composite class loader from drools is using Class.forName that is<br>
>>> being intercepted by the equinox OSGI container -><br>
>>> at<br>
>>> org.eclipse.core.runtime.internal.adaptor.ContextFinder.loadClass(ContextFinder.java:124)<br>
>>> It looks like both are trying to load the same class definition and<br>
>>> the JVM throws the ClassCircularityError.<br>
>>> For my very basic example changing the CompositeClassLoader<br>
>>> implementation to use:<br>
>>><br>
>>> cls = classLoader.loadClass(name);<br>
>>><br>
>>> instead of:<br>
>>> cls = Class.forName( name,<br>
>>> resolve,<br>
>>> classLoader );<br>
>>> Fix the problems. But I'm not sure if that will work for all the other<br>
>>> cases.<br>
>>> Looking the usages of Class.forName inside compiler, core and api I<br>
>>> found that it is being used 39 times, which worries me.<br>
>>> I'm not planning to change all of them without being sure that is the<br>
>>> right way to go. I will continue reading and testing to see if<br>
>>> changing the way of loading the classes is the only alternative.<br>
>>> Some notes about the difference between loadClass and forName:<br>
>>><br>
>>> Classloader.loadClass() caches the loaded class object and returns<br>
>>> always the same class object<br>
>>><br>
>>> This is done by the defining class loader<br>
>>> This ensures that each classloader loads the same class only once<br>
>>><br>
>>> Class.forName() calls the normal classloader hierarchy to load the<br>
>>> class (same happens as above)<br>
>>><br>
>>> But caches the class object within the initiating class loader<br>
>>> In standard cases no problem but can be tricky in dynamic environments<br>
>>><br>
>>> Source<br>
>>> -> <a href="http://www.martinlippert.org/events/WJAX2008-ClassloadingTypeVisibilityOSGi.pdf" target="_blank">http://www.martinlippert.org/events/WJAX2008-ClassloadingTypeVisibilityOSGi.pdf</a><br>
>>> On Tue, Nov 15, 2011 at 4:04 PM, Davide Sottara <<a href="mailto:dsotty@gmail.com">dsotty@gmail.com</a>> wrote:<br>
>>> ><br>
>>> > Lovely exception...<br>
>>> > Well, both my life and salaboy's depend on solving this issue... Mark<br>
>>> > and I<br>
>>> > were also considering to review the Composite ClassLoader at some point<br>
>>> > in<br>
>>> > the future, since it causes issues with (re)declared types in DRLs<br>
>>> > loaded at<br>
>>> > runtime. Looks like we'll have to catch two birds with one stone :)<br>
>>> > Salaboy, can you share the simple service and the WSO2 config details?<br>
>>> > (version, any custom setting, etc...)<br>
>>> ><br>
>>> > --<br>
>>> > View this message in context:<br>
>>> > <a href="http://drools.46999.n3.nabble.com/rules-users-class-loading-problems-with-5-3-0-Final-and-5-4-0-SNAPSHOT-tp3509949p3510640.html" target="_blank">http://drools.46999.n3.nabble.com/rules-users-class-loading-problems-with-5-3-0-Final-and-5-4-0-SNAPSHOT-tp3509949p3510640.html</a><br>
>>> > Sent from the Drools: User forum mailing list archive at Nabble.com.<br>
>>> > _______________________________________________<br>
>>> > rules-users mailing list<br>
>>> > <a href="mailto:rules-users@lists.jboss.org">rules-users@lists.jboss.org</a><br>
>>> > <a href="https://lists.jboss.org/mailman/listinfo/rules-users" target="_blank">https://lists.jboss.org/mailman/listinfo/rules-users</a><br>
>>><br>
>>><br>
>>><br>
>>> --<br>
>>> - CTO @ <a href="http://www.plugtree.com" target="_blank">http://www.plugtree.com</a><br>
>>> - MyJourney @ <a href="http://salaboy.wordpress.com" target="_blank">http://salaboy.wordpress.com</a><br>
>>> - Co-Founder @ <a href="http://www.jugargentina.org" target="_blank">http://www.jugargentina.org</a><br>
>>> - Co-Founder @ <a href="http://www.jbug.com.ar" target="_blank">http://www.jbug.com.ar</a><br>
>>><br>
>>> - Salatino "Salaboy" Mauricio -<br>
>>><br>
>>><br>
>>><br>
>>> --<br>
>>> - CTO @ <a href="http://www.plugtree.com" target="_blank">http://www.plugtree.com</a><br>
>>> - MyJourney @ <a href="http://salaboy.wordpress.com" target="_blank">http://salaboy.wordpress.com</a><br>
>>> - Co-Founder @ <a href="http://www.jugargentina.org" target="_blank">http://www.jugargentina.org</a><br>
>>> - Co-Founder @ <a href="http://www.jbug.com.ar" target="_blank">http://www.jbug.com.ar</a><br>
>>><br>
>>> - Salatino "Salaboy" Mauricio -<br>
>>><br>
>>> _______________________________________________<br>
>>> rules-dev mailing list<br>
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>><br>
>><br>
>> _______________________________________________<br>
>> rules-dev mailing list<br>
>> <a href="mailto:rules-dev@lists.jboss.org">rules-dev@lists.jboss.org</a><br>
>> <a href="https://lists.jboss.org/mailman/listinfo/rules-dev" target="_blank">https://lists.jboss.org/mailman/listinfo/rules-dev</a><br>
>><br>
>><br>
><br>
><br>
><br>
> --<br>
> - CTO @ <a href="http://www.plugtree.com" target="_blank">http://www.plugtree.com</a><br>
> - MyJourney @ <a href="http://salaboy.wordpress.com" target="_blank">http://salaboy.wordpress.com</a><br>
> - Co-Founder @ <a href="http://www.jugargentina.org" target="_blank">http://www.jugargentina.org</a><br>
> - Co-Founder @ <a href="http://www.jbug.com.ar" target="_blank">http://www.jbug.com.ar</a><br>
><br>
> - Salatino "Salaboy" Mauricio -<br>
><br>
<br>
<br>
<br>
--<br>
- CTO @ <a href="http://www.plugtree.com" target="_blank">http://www.plugtree.com</a><br>
- MyJourney @ <a href="http://salaboy.wordpress.com" target="_blank">http://salaboy.wordpress.com</a><br>
- Co-Founder @ <a href="http://www.jugargentina.org" target="_blank">http://www.jugargentina.org</a><br>
- Co-Founder @ <a href="http://www.jbug.com.ar" target="_blank">http://www.jbug.com.ar</a><br>
<br>
- Salatino "Salaboy" Mauricio -<br>
<br>
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</div></div></blockquote></div><br>