Drools version 6.0.0.FINAL I create rule package in Drools workbench and use default knowledgebase and session: KieServices kieServices = KieServices.Factory.get(); KieContainer kContainer = kieServices.newKieContainer(kieServices.newReleaseId("com.test", "validationrules", "1.0-SNAPSHOT")); KieBase kbase = kContainer.getKieBase(); KieSession ksession = kContainer.newKieSession(); I have a query that returns ValidationError: query "getValidationErrors" validationError: ValidationError() end ValidationError is returned and it has values in its fields, but when i try to read fields of that ValidationError fact, i get NullPointerException public class DroolsValidationMessage { private FactType factType; private Object fact; public DroolsValidationMessage(KieBase kbase, Object fact) { this.fact = fact; factType = kbase.getFactType(fact.getClass().getPackage().getName(), fact.getClass().getSimpleName()); } public String getSeverity() { return (String) factType.get(fact, "severity"); // <-- java.lang.NullPointerException } public String getDescription() { return (String) factType.get(fact, "description"); } } factType looks like this: ClassDefinition{className='null', superClass='java.lang.Object', interfaces=[], definedClass=class com.test.validationrules.ValidationError, traitable=null, abstract=false, fields={description=FieldDefinition{name='description', type='java.lang.String', key=false, inherited=false, index=0, initExpr='null', annotations=null, accessor=null}, severity=FieldDefinition{name='severity', type='java.lang.String', key=false, inherited=false, index=1, initExpr='null', annotations=null, accessor=null} This works if the rules and declared class is in resources folder and kmodule.xml is used. KieServices kieServices = KieServices.Factory.get(); KieContainer kContainer = kieServices.getKieClasspathContainer(); KieBase kbase = kContainer.getKieBase("kbase"); KieSession ksession = kContainer.newKieSession("ksession"); factType looks like this: ClassDefinition{className='com.test.validationrules.ValidationError', superClass='java.lang.Object', interfaces=[java.io.Serializable], definedClass=class com.test.validationrules.ValidationError, traitable=NONE, abstract=false, fields={description=FieldDefinition{name='description', type='java.lang.String', key=false, inherited=false, index=0, initExpr='null', annotations=null, accessor=[ClassFieldExtractor class=com.test.validationrules.ValidationError field=description]}, severity=FieldDefinition{name='severity', type='java.lang.String', key=false, inherited=false, index=1, initExpr='null', annotations=null, accessor=[ClassFieldExtractor class=com.test.validationrules.ValidationError field=severity]} -Jarkko -- View this message in context: http://drools.46999.n3.nabble.com/NullPointerException-with-factType-get-... Sent from the Drools: User forum mailing list archive at Nabble.com.