[rules-users] java.lang.NullPointerException in simple example

Hi guys! I'm new in the world of jboss and drools and I'm making some simple examples that existing on https://github.com/droolsjbpm/drools/tree/master/drools-examples-api Now, I'm studing the CashFlow example and in my project when I run it, I receive a error message saying: Exception in thread "main" java.lang.NullPointerException at com.sample.CashFlowMain.main(CashFlowMain.java:30)" I don't know the why this message, because I set the acp at lines 20 and 21. Someone would help me please? Thanks package com.sample; import org.kie.api.KieServices; import org.kie.api.runtime.KieContainer; import org.kie.api.runtime.KieSession; import org.kie.api.runtime.rule.FactHandle; import java.text.SimpleDateFormat; import java.util.Date; public class CashFlowMain { public static void main(String[] args) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); KieContainer kc = KieServices.Factory.get().getKieClasspathContainer(); KieSession ksession = kc.newKieSession("CashFlowKS"); AccountPeriod acp = new AccountPeriod(); acp.setStart(date("2013-01-01")); // set acp - line 20 acp.setEnd(date("2013-03-31")); // set acp - line 21 Account ac = new Account(1, 0); CashFlow cf1 = new CashFlow(date( "2013-01-12"), 100, CashFlowType.CREDIT, 1 ); CashFlow cf2 = new CashFlow(date( "2013-02-2"), 200, CashFlowType.DEBIT, 1 ); CashFlow cf3 = new CashFlow(date( "2013-05-18"), 50, CashFlowType.CREDIT, 1 ); CashFlow cf4 = new CashFlow(date( "2013-03-07"), 75, CashFlowType.CREDIT, 1 ); FactHandle fh = ksession.insert(acp); ksession.insert( ac ); ksession.insert( cf1 ); ksession.insert( cf2 ); ksession.insert( cf3 ); ksession.insert( cf4 ); ksession.fireAllRules(); acp.setStart(date( "2013-04-01")); acp.setEnd(date( "2013-06-31")); ksession.update(fh, acp); ksession.fireAllRules(); } public static Date date(String str) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); return sdf.parse( str ); } } -- View this message in context: http://drools.46999.n3.nabble.com/java-lang-NullPointerException-in-simpl... Sent from the Drools: User forum mailing list archive at Nabble.com.