Esteban,

Here is the stack trace for the ClassNotFoundException when the compiler jar is not included.

java.lang.ClassNotFoundException: org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387)

at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)

at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Class.java:169)

at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:190)

at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.call(ServiceRegistryImpl.java:185)

at org.drools.util.ServiceRegistryImpl.get(ServiceRegistryImpl.java:143)

at org.drools.builder.KnowledgeBuilderFactory.loadServiceFactory(KnowledgeBuilderFactory.java:107)

at org.drools.builder.KnowledgeBuilderFactory.getKnowledgeBuilderPServiceFactory(KnowledgeBuilderFactory.java:101)

at org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilder(KnowledgeBuilderFactory.java:29)

at org.drools.agent.impl.KnowledgeAgentImpl.createPackageFromResource(KnowledgeAgentImpl.java:556)

at org.drools.agent.impl.KnowledgeAgentImpl.createPackageFromResource(KnowledgeAgentImpl.java:541)

at org.drools.agent.impl.KnowledgeAgentImpl.incrementalBuildResources(KnowledgeAgentImpl.java:731)

at org.drools.agent.impl.KnowledgeAgentImpl.buildKnowledgeBase(KnowledgeAgentImpl.java:515)

at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:145)

at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:130)

Any idea on why the other error is appearing. The error is “java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage”. This occurs when the knowledge agent is created with the compiled package from the Guvnor for the first time.

Thank you for all your work and help. Drools is a great package.

Thanks.

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Esteban Aliverti
Sent: Thursday, July 01, 2010 8:09 AM
To: Rules Users List
Subject: Re: [rules-users] Drools and Guvnor 5.1M2 - Exception beingthrowninprocessChangeSet

Could you please provide us the line number where de ClassNotFoundException occurs. I think I know what could be happening. When you use incremental change set processing (newInstance = false), the agent use a kbuilder to perform some diff between the modified and original resource. The thing is that the agent always instantiate a kbuilder even if all the resources are already compiled (which is useless).

Please provide me the line number of the exception, i will start working on this issue. Meanwhile, as a workaround, add the drools-compiler dependency.

The KAgent was practically rebuilt from scratch since 5.1M1 so these kind of error were expected ;)

Best,

2010/7/1 Jeffrey Schneller <jeffrey.schneller@envisa.com>

As a follow-up, this did work however there are still some problems. The rules did get pulled into the application and seem to be running but clearly something is not right.

I needed to include the drools-compiler.jar in my app otherwise I was getting a ClassNotFoundException. I am pulling a compiled package from the Guvnor so not sure why I need the compiler jar in my app.

When the rules are pulled into the app I am getting the exception thrown which is being logged and the app can continue running:

2010-07-01 00:36:14,201 | INFO (MyDroolsListener.java:41) KnowledgeAgent performing an incremental build of the ChangeSet

2010-07-01 00:36:14,261 | ERROR (MyDroolsListener.java:30) java.lang.RuntimeException: KnowledgeAgent exception while trying to deserialize KnowledgeDefinitionsPackage

2010-07-01 00:36:14,261 | WARN (MyDroolsListener.java:53) KnowledgeAgent: The resource didn't create any package: [UrlResource path='http://ruleserver/drools-guvnor/org.drools.guvnor.Guvnor/package/my.rule.package/LATEST']

2010-07-01 00:36:14,271 | INFO (MyDroolsListener.java:41) KnowledgeAgent incremental build of KnowledgeBase finished and in use

Then if I rebuild the package in the Guvnor then I see the following [the two lines are repeated for each rule in the package]:

[2010:07:182 00:07:741:debug] BinaryResourceDiffProducerImpl: Comparing [Rule name=v_32, agendaGroup=MAIN, salience=0, no-loop=false] against [Rule name=v_32, agendaGroup=MAIN, salience=0, no-loop=false]

[2010:07:182 00:07:741:debug] BinaryResourceDiffProducerImpl: The rules have different LHS

Thanks

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Esteban Aliverti
Sent: Wednesday, June 30, 2010 6:35 PM

To: Rules Users List
Subject: Re: [rules-users] Drools and Guvnor 5.1M2 - Exception beingthrownin processChangeSet

The problem seams to happen because the kagent can't access the url.

If you try to access the change set xml using a browser, does the browser ask you for authentication? I don't know why, but guvnor protect its urls since 5.1 I think.

So, basically, the error is that guvnor can't read from the url. The same error happens if you provide a non existent url. I need to open a jira for this.

As a work around, try doing this:

<change-set xmlns='http://drools.org/drools-5.0/change-set'

xmlns:xs='http://www.w3.org/2001/XMLSchema-instance'

xs:schemaLocation='http://drools.org/drools-5.0/change-set drools-change-set-5.0.xsd' >

<add>

</add>

</change-set>

Remember to replace username and password.

Best,

2010/6/30 Jeffrey Schneller <jeffrey.schneller@envisa.com>

Here is the xml file I am getting:

<change-set xmlns='http://drools.org/drools-5.0/change-set'

xmlns:xs='http://www.w3.org/2001/XMLSchema-instance'

xs:schemaLocation='http://drools.org/drools-5.0/change-set drools-change-set-5.0.xsd' >

<add>

</add>

</change-set>

From: rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Esteban Aliverti
Sent: Wednesday, June 30, 2010 3:18 PM
To: Rules Users List
Subject: Re: [rules-users] Drools and Guvnor 5.1M2 - Exception being thrownin processChangeSet

Could you please post the xml file you are getting from http://rulerserver/drools-guvnor/org.drools.guvnor.Guvnor/package/my.rule.package/LATEST/ChangeSet.xml?

Best,

2010/6/30 Jeffrey Schneller <jeffrey.schneller@envisa.com>

I am trying to upgrade to the 5.1M2 build from 5.0.1 and am running into some issues. I have installed the new 5.1 Guvnor and imported the rules from my 5.0.1 Guvnor instance.

I then removed the old 5.0.1 drools jars from my app and replaced them with the 5.1M2 drools jars. I was also added all the dependent libraries. The code that worked with the 5.0.1 version does not work with the 5.1M2 version. In 5.0.1 I was constructing the xml and streaming it into the applyChangeSet method. With 5.1M2 I am just pointing to the change set xml file that is in the Guvnor.

I am seeing a NullPointerException being thrown in the processChangeSet method as shown below.

Caused by: java.lang.NullPointerException

at org.drools.agent.impl.KnowledgeAgentImpl.processChangeSet(KnowledgeAgentImpl.java:171)

at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:143)

at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentImpl.java:130)

Did I miss something? Am I doing something wrong? Below is the code that I have.

KnowledgeAgentConfiguration kaconf = KnowledgeAgentFactory.newKnowledgeAgentConfiguration();

kaconf.setProperty( "drools.agent.scanDirectories", "true" );

kaconf.setProperty("drools.agent.newInstance", "false");

ResourceFactory.getResourceChangeScannerService().start();

ResourceFactory.getResourceChangeNotifierService().start();

String url = "http://rulerserver/drools-guvnor/org.drools.guvnor.Guvnor/package/my.rule.package/LATEST/ChangeSet.xml";

KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent( "Configuration", kaconf );

kagent.setSystemEventListener(new MyDroolsListener());

try {

kagent.applyChangeSet(ResourceFactory.newUrlResource(new URL(url))); // ERROR IS OCCURING INSIDE OF applyChangeSet

} catch (MalformedURLException e) {

e.printStackTrace();

}

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Esteban Aliverti

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rules-users mailing list
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Esteban Aliverti

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Esteban Aliverti