Consider the rule file: SimpleRuleWithAccumulate.drl dialect "mvel" dialect "java" declare MySum val : Integer @key end rule "Simple rule 2" when accumulate($i : Integer(intValue > 5); $s : sum($i)) then insertLogical(new MySum($s)) end The test which reproduces the bug: @Test public void ruleRemovalTest() { /** Create the kie container based on a simple rule from SimpleRuleWithAccumulate.drl */ KieServices kieServices = KieServices.Factory.get(); KieFileSystem kieFileSystem = kieServices.newKieFileSystem(); kieFileSystem.write(ResourceFactory.newFileResource("src/test/java/rulesengine/SimpleRuleWithAccumulate.drl")); KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem); kieBuilder.buildAll(); KieModule kieModule = kieBuilder.getKieModule(); KieContainer kieContainer = kieServices.newKieContainer(kieModule.getReleaseId()); KieSession kieSession = kieContainer.newKieSession(); /** Insert three Integer objects: 3, 7, 9 */ kieSession.insert(new Integer(3)); kieSession.insert(new Integer(7)); kieSession.insert(new Integer(9)); Assert.assertEquals(3, kieSession.getObjects().size()); /** Fire all rules, verify that one object of type MySum is created */ kieSession.fireAllRules(); System.out.println("***************************************************"); System.out.println("Objects in the working memory after all rules fired"); for (Object o : kieSession.getObjects()) { System.out.println(o); } System.out.println("***************************************************"); Assert.assertEquals(4, kieSession.getObjects().size()); /** * Update the kie base using the kie module which no longer contains * SimpleRuleWithAccumulate.drl */ kieFileSystem = kieServices.newKieFileSystem(); kieBuilder = kieServices.newKieBuilder(kieFileSystem); kieBuilder.buildAll(); kieModule = kieBuilder.getKieModule(); kieContainer.updateToVersion(kieModule.getReleaseId()); KieBase kieBase = kieContainer.getKieBase(); kieBase.removeRule("defaultpkg", "Simple rule 2"); /** * Fire all rules. Logically inserted objects of MySum should be automatically * removed from the working memory */ kieSession.fireAllRules(); System.out.println("***************************************************"); System.out.println("Objects in the working memory after the SimpleRule.drl is removed"); for (Object o : kieSession.getObjects()) { System.out.println(o); } System.out.println("***************************************************"); Assert.assertEquals(3, kieSession.getObjects().size()); }