Hello, Im having trouble with the BRMS front end throwing an: Exception in thread "main" java.lang.ClassCastException: java.util.HashSet cannot be cast to java.util.List at org.drools.rule.Package.readExternal(Package.java:172) This is what I have set up: jbossweb-1.0.1.GA drools-4.0.1-brms Java version 1.6.0 - VM 1.6.0-b105 mvel jar file: mvel14-1.2rc4rv908 (taken from the jbossweb lib) This is the class, which i put into a .jar, which in turn I import into the front end: package data; import java.io.Serializable; public class ExceptionType implements Serializable{ private String customerType = ""; private String exceptionType = ""; public ExceptionType(){} public ExceptionType(String customerType, String exceptionType) { this.exceptionType = exceptionType; this.customerType = customerType; } public void setExceptionType(String exceptionType) { this.exceptionType = exceptionType; } public String getExceptionType() { return exceptionType; } public void setCustomerType(String customerType) { this.customerType = customerType; } public String getCustomerType() { return customerType; } } And here is the starting point: package data; import java.util.Properties; import org.drools.RuleBase; import data.ExceptionType; import org.drools.StatefulSession; import org.drools.agent.RuleAgent; public class Runner { public Runner() { ExceptionType e = new ExceptionType("das", "32432"); e.setExceptionType("system failure"); Properties prop = new Properties(); prop.setProperty("newInstance", "true"); prop.setProperty("url","http://localhost:8080/drools-jbrms/org.drools.brms.JBRMS/package/defaultPackage/snap2"); prop.setProperty("poll", "30"); RuleAgent agent = RuleAgent.newRuleAgent(prop); //error occurs on this line. RuleBase rb = agent.getRuleBase(); StatefulSession session = rb.newStatefulSession(); session.insert(e); session.fireAllRules(); } /** * @param args */ public static void main(String[] args) { new Runner(); } } I have specified a package import in the packge in the front end: import data.ExceptionType Validation of the .jar file and build of the package seem to work fine. Here is the complete stack trace: RuleAgent(default) INFO (Fri Sep 28 21:57:54 NZST 2007): Configuring with newInstance=true, secondsToRefresh=30 RuleAgent(default) INFO (Fri Sep 28 21:57:54 NZST 2007): Configuring package provider : URLScanner monitoring URLs: http://localhost:8080/drools-jbrms/org.drools.brms.JBRMS/package/defaultP... Exception in thread "main" java.lang.ClassCastException: java.util.HashSet cannot be cast to java.util.List at org.drools.rule.Package.readExternal(Package.java:172) at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1792) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1751) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351) at org.drools.agent.HttpClientImpl.fetchPackage(HttpClientImpl.java:54) at org.drools.agent.URLScanner.readPackage(URLScanner.java:137) at org.drools.agent.URLScanner.getChangeSet(URLScanner.java:109) at org.drools.agent.URLScanner.loadPackageChanges(URLScanner.java:88) at org.drools.agent.RuleAgent.checkForChanges(RuleAgent.java:297) at org.drools.agent.RuleAgent.refreshRuleBase(RuleAgent.java:265) at org.drools.agent.RuleAgent.configure(RuleAgent.java:251) at org.drools.agent.RuleAgent.init(RuleAgent.java:183) at org.drools.agent.RuleAgent.newRuleAgent(RuleAgent.java:140) at data.Runner.<init>(Runner.java:25) at data.Runner.main(Runner.java:37) Any help would be appreciated. Thanks, Wojtek Kedzior First Data Utilities Auckland, New Zealand Software Engineering