sample.java

 public static final void main(String[] args) {
        try {
            // load up the knowledge base
            KieServices ks = KieServices.Factory.get();
            KieContainer kContainer = ks.getKieClasspathContainer();
            KieSession kSession = kContainer.newKieSession("ksession-rules");

            // go !
            Message message = new Message();
            message.setMessage("Hello World");
            message.setStatus(Message.HELLO);

            Message message2 = new Message();
            message.setMessage("Hello World");
            message.setStatus(Message.HELLO);
            FactHandle h = kSession.insert(message);
            FactHandle h1 = kSession.insert(message2);

            kSession.fireAllRules();

            kSession.delete(h);
            kSession.delete(h1);