Hi, I’m using the EMF model editor of the project MDT/BPMN2 to edit BPMN models and I’d like to use Drools to validate my models. However, when the code line: KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); is called into the editor application, I get the following error: !ENTRY org.eclipse.ui 4 0 2013-08-22 15:56:32.784 !MESSAGE Unhandled event loop exception !STACK 0 org.eclipse.e4.core.di.InjectionException: java.lang.NoClassDefFoundError: org/drools/builder/KnowledgeBuilderFactory at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:63) at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:229) at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:210) at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:131) at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:171) at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.executeItem(HandledContributionItem.java:851) at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.handleWidgetSelection(HandledContributionItem.java:744) at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.access$7(HandledContributionItem.java:728) at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem$4.handleEvent(HandledContributionItem.java:667) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4169) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3758) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1022) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:916) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86) at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:585) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:540) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584) at org.eclipse.equinox.launcher.Main.run(Main.java:1438) at org.eclipse.equinox.launcher.Main.main(Main.java:1414) I’ve already added standard Drools runtime libs to build path, but the error goes on. Can someone help me? Thanks, Raquel -- View this message in context: http://drools.46999.n3.nabble.com/Problem-initializing-Drools-from-EMF-mo... Sent from the Drools: User forum mailing list archive at Nabble.com.