I did some search here and found using jbpm-bpmn2 dependency will get rid of the following error. <dependency> <groupId>org.jbpm</groupId> <artifactId>jbpm-bpmn2</artifactId> <version>5.3.0.CR1</version> </dependency> Is this the correct soluation? If there is such an dependency, should not the drools-core be taking care of this in the pom file? Now I tried to add the dependency myself but ended up with some method not found exception, which I believe is caused by the version mismatching (since I do not know which version would match drools 5.3.0.final). I would assume using ruleflow is common practice in this forum. does anyone else have this issue when working with 5.3.0.Final? Thanks Sean "java.lang.RuntimeException: Unable to instantiate a process builder" .... Caused by: java.lang.ClassNotFoundException: org.jbpm.process.builder.ProcessBuilderFactoryServiceImpl at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:169) at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:207) -- "But beware of the Dark Side. Anger, fear, aggression - the Dark Side of the Force are they." -Yoda