Thanks Mario. The fact and properties are generated from object in our system, it may reach the limitation cause the fields of object may be larger than 64. If propertyreactive is disabled, when fire the rule, it will throw ClassCastException: class a.b can not be cast to a.b, it's very strange cause it's same class. If I remove the @propertyreactive in drl file, even amount of properties is less than 64, such as only 1 or 2, it will throw the ClassCastException too, not sure why this would happen. -- View this message in context: http://drools.46999.n3.nabble.com/Why-disable-properyreactive-if-amount-o... Sent from the Drools: User forum mailing list archive at Nabble.com.

The drools we are using is forked from github, the last commit happened at Apr 24, 2013, https://github.com/droolsjbpm/drools/commit/c6d3175c013b1a93d5bec99af7521... Following is the code for building knowledge base: _kbase = new KnowledgeBaseImpl(new ReteooRuleBase(id, null)); For registering drl code to knowledge base: Properties props = new Properties(); props.setProperty("drools.dialect.java.compiler", "JANINO"); KnowledgeBuilderConfiguration conf = KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(props, null); final KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(conf); kbuilder.add(ResourceFactory.newInputStreamResource(new ByteArrayInputStream(drlCode.getBytes())), ResourceType.DRL); _ksession.execute(new GenericCommand<Void>() { @Override public Void execute(Context ctxt) { _ksession.getKieBase().addKnowledgePackages( kbuilder.getKnowledgePackages()); try { _kbaseStore.saveKnowledgeBase(); } catch (IOException e) { throw new RuntimeException(e); } return null; } }); The drl code: package test_input declare input type : String end declare output taskname : String end rule "Rule A" dialect "mvel" salience 0 no-loop when $input:input(type == "a") $output:output() then modify ($output) {taskname = "Hello"}; end Stace trace(Not full, others are just the logic in our system, such as router, find rules, etc.): java.lang.ClassCastException: test_input.input cannot be cast to test_input.input at org.drools.base.test_input.input1271536688$setType.setValue(Unknown Source) ~[na:na] at org.drools.core.base.ClassFieldWriter.setValue(ClassFieldWriter.java:164) ~[org.drools.core_6.0.0.20130429-0424.jar:6.0.0.024] at org.drools.core.base.ClassFieldAccessor.setValue(ClassFieldAccessor.java:330) ~[org.drools.core_6.0.0.20130429-0424.jar:6.0.0.024] at org.drools.core.factmodel.ClassDefinition.set(ClassDefinition.java:244) ~[org.drools.core_6.0.0.20130429-0424.jar:6.0.0.024] -- View this message in context: http://drools.46999.n3.nabble.com/Why-disable-properyreactive-if-amount-o... Sent from the Drools: User forum mailing list archive at Nabble.com.

Unfortunately, remove Janino did not resolve my problem. -- View this message in context: http://drools.46999.n3.nabble.com/Why-disable-properyreactive-if-amount-o... Sent from the Drools: User forum mailing list archive at Nabble.com.

A lot has changed since April. You'll need to build master and try it against that. If the issue not related to more than 64 fields, you'll need to write a unit test against master. http://docs.jboss.org/drools/release/5.5.0.Final/droolsjbpm-introduction-... Mark On 17 Oct 2013, at 03:23, richie <haoruiqian(a)gmail.com&gt; wrote: