Hello, I was trying to build a kie module and programmatically load DRL rules at runtime. But I found for any new event type I wanted to monitor, I had to add "@rule(event)" when I 1st created the module. If I didn't, I would get the following exception when I tried to updateToVersion. My java file is also attached. Would some one please let me know what caused my problem? And anyway to get around this problem? We really need to get the programmatically loading rules working in our project. Thanks a lot. PlayGround1.java <http://drools.46999.n3.nabble.com/file/n4028783/PlayGround1.java> Exception in thread "main" java.lang.NullPointerException at org.drools.core.common.ProjectClassLoader$InternalTypesClassLoader.defineClass(ProjectClassLoader.java:230) at org.drools.core.common.ProjectClassLoader.defineType(ProjectClassLoader.java:141) at org.drools.core.common.ProjectClassLoader.defineClass(ProjectClassLoader.java:152) at org.drools.compiler.kie.builder.impl.KieContainerImpl.updateToVersion(KieContainerImpl.java:191) at com.some.app.PlayGround1.runRules(PlayGround1.java:72) at com.some.app.PlayGround1.main(PlayGround1.java:34) -- View this message in context: http://drools.46999.n3.nabble.com/Programmatically-load-rules-classloader... Sent from the Drools: User forum mailing list archive at Nabble.com.