Hello everyone, I am new to Drools and has been working and studying on it for the past 3 weeks. I'm currently working on a project using JBoss Seam and WebLogic (I'm new to these technologies also), and there are quite number of rules that need to be implemented to the system. Below is the stack trace after I clicked on an action button from the UI that will trigger the rule action: java.lang.NoClassDefFoundError: org/antlr/runtime/Parser at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:620) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) at java.net.URLClassLoader.defineClass(URLClassLoader.java:260) at java.net.URLClassLoader.access$000(URLClassLoader.java:56) at java.net.URLClassLoader$1.run(URLClassLoader.java:195) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) at org.drools.compiler.DrlParser.getParser(DrlParser.java:207) at org.drools.compiler.DrlParser.parse(DrlParser.java:60) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:165) at com.fms.newss.rule.util.RuleUtil_beaVersion0_938.readRule(RuleUtil.java:44) at com.fms.newss.rule.util.RuleUtil.readRule(RuleUtil.java) at com.fms.newss.rule.action.RuleAction_beaVersion0_662.doValidateRules(RuleAction.java:85) at com.fms.newss.rule.action.RuleAction.doValidateRules(RuleAction.java) at com.fms.newss.rule.action.DummyMain_beaVersion0_656.doRule(DummyMain.java:81) at com.fms.newss.rule.action.DummyMain.doRule(DummyMain.java) at com.fms.newss.rule.action.DummyMain.<init>(DummyMain.java:55) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.jboss.seam.Component.instantiateJavaBean(Component.java:1395) at org.jboss.seam.Component.instantiate(Component.java:1316) at org.jboss.seam.Component.newInstance(Component.java:2074) at org.jboss.seam.Component.getInstance(Component.java:1978) at org.jboss.seam.Component.getInstance(Component.java:1940) at org.jboss.seam.Component.getInstance(Component.java:1934) at org.jboss.seam.Namespace.getComponentInstance(Namespace.java:55) at org.jboss.seam.Namespace.getComponentInstance(Namespace.java:50) at org.jboss.seam.el.SeamELResolver.resolveBase(SeamELResolver.java:166) at org.jboss.seam.el.SeamELResolver.getValue(SeamELResolver.java:53) at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:143) at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:64) at org.jboss.el.parser.AstIdentifier.getValue(AstIdentifier.java:44) at org.jboss.el.parser.AstValue.getTarget(AstValue.java:34) at org.jboss.el.parser.AstValue.invoke(AstValue.java:95) at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276) at com.sun.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:68) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:77) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91) at javax.faces.component.UICommand.broadcast(UICommand.java:383) at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:321) at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:296) at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:253) at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:466) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:244) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:38) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:390) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:517) at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.utils.FastSwapFilter.doFilter(FastSwapFilter.java:66) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3496) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(Unknown Source) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) Caused by: java.lang.ClassNotFoundException: org.antlr.runtime.Parser at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) ... 93 more java.lang.NoClassDefFoundError: org/drools/lang/DRLParser at org.drools.compiler.DrlParser.getParser(DrlParser.java:207) at org.drools.compiler.DrlParser.parse(DrlParser.java:60) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:165) at com.fms.newss.rule.util.RuleUtil_beaVersion0_938.readRule(RuleUtil.java:44) at com.fms.newss.rule.util.RuleUtil.readRule(RuleUtil.java) at com.fms.newss.rule.action.RuleAction_beaVersion0_662.doValidateRules(RuleAction.java:85) at com.fms.newss.rule.action.RuleAction.doValidateRules(RuleAction.java) at com.fms.newss.rule.action.DummyMain_beaVersion0_656.doRule(DummyMain.java:81) at com.fms.newss.rule.action.DummyMain.doRule(DummyMain.java) at com.fms.newss.rule.action.DummyMain_$$_javassist_20._d23doRule(DummyMain_$$_javassist_20.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at javassist.util.proxy.RuntimeSupport$1.invoke(RuntimeSupport.java:34) at com.fms.newss.rule.action.DummyMain_$$_javassist_20.doRule(DummyMain_$$_javassist_20.java) at com.fms.newss.rule.action.DummyMain.<init>(DummyMain.java:55) at com.fms.newss.rule.action.DummyMain_$$_javassist_20.<init>(DummyMain_$$_javassist_20.java) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.jboss.seam.Component.wrap(Component.java:1461) at org.jboss.seam.Component.instantiateJavaBean(Component.java:1399) at org.jboss.seam.Component.instantiate(Component.java:1316) at org.jboss.seam.Component.newInstance(Component.java:2074) at org.jboss.seam.Component.getInstance(Component.java:1978) at org.jboss.seam.Component.getInstance(Component.java:1940) at org.jboss.seam.Component.getInstance(Component.java:1934) at org.jboss.seam.Namespace.getComponentInstance(Namespace.java:55) at org.jboss.seam.Namespace.getComponentInstance(Namespace.java:50) at org.jboss.seam.el.SeamELResolver.resolveBase(SeamELResolver.java:166) at org.jboss.seam.el.SeamELResolver.getValue(SeamELResolver.java:53) at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:143) at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:64) at org.jboss.el.parser.AstIdentifier.getValue(AstIdentifier.java:44) at org.jboss.el.parser.AstValue.getTarget(AstValue.java:34) at org.jboss.el.parser.AstValue.invoke(AstValue.java:95) at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276) at com.sun.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:68) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:77) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91) at javax.faces.component.UICommand.broadcast(UICommand.java:383) at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:321) at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:296) at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:253) at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:466) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:244) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:38) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:390) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:517) at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.utils.FastSwapFilter.doFilter(FastSwapFilter.java:66) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3496) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(Unknown Source) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) java.lang.NoClassDefFoundError: org/drools/lang/DRLParser at org.drools.compiler.DrlParser.getParser(DrlParser.java:207) at org.drools.compiler.DrlParser.parse(DrlParser.java:60) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:165) at com.fms.newss.rule.util.RuleUtil_beaVersion0_938.readRule(RuleUtil.java:44) at com.fms.newss.rule.util.RuleUtil.readRule(RuleUtil.java) at com.fms.newss.rule.action.RuleAction_beaVersion0_662.doValidateRules(RuleAction.java:85) at com.fms.newss.rule.action.RuleAction.doValidateRules(RuleAction.java) at com.fms.newss.rule.action.DummyMain_beaVersion0_656.doRule(DummyMain.java:81) at com.fms.newss.rule.action.DummyMain.doRule(DummyMain.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.jboss.seam.util.Reflections.invoke(Reflections.java:22) at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56) at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:28) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:77) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.bpm.BusinessProcessInterceptor.aroundInvoke(BusinessProcessInterceptor.java:51) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:44) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107) at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:166) at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:102) at com.fms.newss.rule.action.DummyMain_$$_javassist_20.doRule(DummyMain_$$_javassist_20.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:329) at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:342) at org.jboss.el.parser.AstPropertySuffix.invoke(AstPropertySuffix.java:58) at org.jboss.el.parser.AstValue.invoke(AstValue.java:96) at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276) at com.sun.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:68) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:77) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:91) at javax.faces.component.UICommand.broadcast(UICommand.java:383) at org.ajax4jsf.component.AjaxViewRoot.processEvents(AjaxViewRoot.java:321) at org.ajax4jsf.component.AjaxViewRoot.broadcastEvents(AjaxViewRoot.java:296) at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:253) at org.ajax4jsf.component.AjaxViewRoot.processApplication(AjaxViewRoot.java:466) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:97) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:117) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:244) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83) at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:38) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178) at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290) at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:390) at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:517) at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:56) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58) at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.utils.FastSwapFilter.doFilter(FastSwapFilter.java:66) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27) at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3496) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(Unknown Source) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) Below is the list of deployed-jboss-jars-ear.list antlr-runtime.jar core.jar drools-compiler.jar drools-core.jar janino.jar jboss-el.jar jbpm-jpdl.jar mvel14.jar jsf-facelets.jar richfaces-api.jar richfaces-impl.jar richfaces-ui.jar commons-*.jar quartz-all-*.jar I've been trying to solve this issues since a few days back. However I couldn't find the solution. It worked fine previously until I updated my project folder from the cvs. I'm afraid that there could be any missing jars. Hope anyone could help me. Thank you very much.