Assessment failed due to the following error(s): java.lang.NullPointerException
Stacktrace:
java.lang.NullPointerException
 at org.mvel2.MVEL.executeExpression(MVEL.java:953)
 at org.kie.soup.project.datamodel.commons.util.RawMVELEvaluator.executeExpression(RawMVELEvaluator.java:113)
 at org.drools.core.base.extractors.MVELObjectClassFieldReader.getValue(MVELObjectClassFieldReader.java:140)
 at org.drools.core.base.extractors.BaseObjectClassFieldReader.getHashCode(BaseObjectClassFieldReader.java:180)
 at org.drools.core.rule.Declaration.getHashCode(Declaration.java:267)
 at org.drools.core.util.AbstractHashTable$FieldIndex.hashCodeOf(AbstractHashTable.java:343)
 at org.drools.core.util.AbstractHashTable$SingleIndex.hashCodeOf(AbstractHashTable.java:409)
 at org.drools.core.util.index.TupleIndexHashTable.getOrCreate(TupleIndexHashTable.java:392)
 at org.drools.core.util.index.TupleIndexHashTable.add(TupleIndexHashTable.java:358)
 at org.drools.core.phreak.PhreakAccumulateNode.doLeftInserts(PhreakAccumulateNode.java:139)
 at org.drools.core.phreak.PhreakAccumulateNode.doNode(PhreakAccumulateNode.java:89)
 at org.drools.core.phreak.RuleNetworkEvaluator.switchOnDoBetaNode(RuleNetworkEvaluator.java:581)
 at org.drools.core.phreak.RuleNetworkEvaluator.evalBetaNode(RuleNetworkEvaluator.java:552)
 at org.drools.core.phreak.RuleNetworkEvaluator.evalNode(RuleNetworkEvaluator.java:379)
 at org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:339)
 at org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:175)
 at org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:133)
 at org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:212)
 at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:87)
 at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:34)
 at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
 at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1066)
 at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1013)
 at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1005)
 at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1330)
 at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
 at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1305)