Hello all,

I've been reading up about drool-spring integration and have put together a simple project that wires together a KnowledgeBase and KnowledgeSession as follows : 

<drools:resource id="GroupUnit" type="DRL"

source="file:/Users/drools/drools-spring-test/src/Rules/drls/GroupUnit.drl" />

<drools:resource id="GradeUnit" type="DRL"

source="file:/Users/drools/drools-spring-test/src/Rules/drls/GradeUnit.drl"" />

<drools:resource id="EvaluateUnit" type="DRL"

source="file:/Users/drools/drools-spring-test/src/Rules/drls/EvaluateUnit.drl"" />

<drools:grid-node id="node1" />

<drools:kbase id="kbase1" node="node1">


<drools:resource ref="GroupUnit" />

<drools:resource ref="GradeUnit" />

<drools:resource ref="EvaluateUnit" />



<drools:ksession id="ksession" type="stateful" kbase="kbase1"

node="node1" />

Then in my Controller call, I 'AutoWire' in the StatefulKnowledgeSession as follows :


@RequestMapping( value = "foo" )

final class FooController{



   StatefulKnowledgeSession ksession;


   @RequestMapping(  method = RequestMethod.GET )


   public String evaluateUnit() {


Unit unit = new Unit("030", "502", "C", "9484", "45", new String[] {},



  if (ksession != null) {




  return "<UnitCategory>" + unit.getUnitCategory() + "</UnitCategory>";



  return "<message> stateful session is null</message>";


The main question that I have is that is this solution thread-safe ? From what I understand of spring is that beans configured without any additional qualifiers are inherently singletons. And when deployed in a multi-theaded container like tomcat, Spring assumes that the beans being severed up a thread-safe. So from I have read is that KnowledeSessions are inherently not thread safe. So putting the 2 together, I leaning towards the assessment that this above solution is NOT thread safe and that if I do want it to be thread safe I should set the StatefulKnowledgeSession to 'prototype' and not leave it as a singleton.

Please let me know if I'm missing anything in my assessment here !

Thanks in advance,

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