[rules-users] concurrent execution for the first time thorws error

[Sudhir M]

Hi,

In our application we have different rulesets which we load them on
demand and cache them (knowledge base) for the sub-sequent requests.

For the first time before caching if we hit the server concurrently we
are getting the following exception which is not very clear.

I assume knowledge bases are thread safe and we can create multiple
stateful sessions using the same knowledege base.

we are using drools 5.1 final release.

java.lang.IllegalArgumentException: org.drools.process.instance.impl
	at java.lang.ClassLoader.definePackage(ClassLoader.java:1452)
	at java.net.URLClassLoader.definePackage(URLClassLoader.java:348)
	at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:1781)
	at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:866)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1319)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1198)
	at org.drools.SessionConfiguration.initProcessInstanceManagerFactory(SessionConfiguration.java:302)
	at org.drools.SessionConfiguration.getProcessInstanceManagerFactory(SessionConfiguration.java:291)
	at org.drools.common.AbstractWorkingMemory.<init>(AbstractWorkingMemory.java:367)
	at org.drools.common.AbstractWorkingMemory.<init>(AbstractWorkingMemory.java:295)
	at org.drools.common.AbstractWorkingMemory.<init>(AbstractWorkingMemory.java:259)
	at org.drools.reteoo.ReteooWorkingMemory.<init>(ReteooWorkingMemory.java:96)
	at org.drools.reteoo.ReteooStatefulSession.<init>(ReteooStatefulSession.java:80)
	at org.drools.reteoo.ReteooRuleBase.newStatefulSession(ReteooRuleBase.java:386)
	at org.drools.reteoo.ReteooRuleBase.newStatefulSession(ReteooRuleBase.java:371)
	at org.drools.impl.KnowledgeBaseImpl.newStatefulKnowledgeSession(KnowledgeBaseImpl.java:172)
	at org.drools.impl.KnowledgeBaseImpl.newStatefulKnowledgeSession(KnowledgeBaseImpl.java:155)

Please help us in this regard.

Thanks
sudhir.