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Exception while executing a class associated with user task

vijayd
Champ in-the-making
Champ in-the-making
I have associated a class to a user task and that task is assigned to kermit. Now when kermit commits the task, the class must be instantiate and execute ; But, I am getting an exception unable to instantiate a class "demo.tasklistener.DemoTaskListener" on activiti explorer and following error on the Tomcat :

12 Mar, 2014 11:52:04 AM org.apache.catalina.connector.CoyoteAdapter service
SEVERE: An exception or error occurred in the container during the request proce
ssing
java.lang.NoClassDefFoundError: com/vaadin/terminal/gwt/server/AbstractApplicati
onServlet
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14
1)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at org.apache.catalina.core.StandardWrapper.servletSecurityAnnotationSca
n(StandardWrapper.java:1139)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(Authentica
torBase.java:451)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:164)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:100)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:
562)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:118)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:395)
        at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcesso
r.java:306)
        at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.pr
ocess(Http11AprProtocol.java:323)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:1719)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.ClassNotFoundException: com.vaadin.terminal.gwt.server.Abst
ractApplicationServlet
        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:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        … 24 more
11:52:17,663 ["http-apr-8080"-exec-7] ERROR org.activiti.engine.impl.interceptor
.CommandContext  - Error while closing command context
org.activiti.engine.ActivitiException: Exception while invoking TaskListener: de
mo.tasklistener.DemoTaskListener doesn't implement interface org.activiti.engine
.delegate.TaskListener
        at org.activiti.engine.impl.persistence.entity.TaskEntity.fireEvent(Task
Entity.java:553)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskE
ntity.java:146)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.
java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.
java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTa
skCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandInvoker.execute(CommandIn
voker.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execut
e(CommandContextInterceptor.java:57)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(Sp
ringTransactionInterceptor.java:47)
        at org.springframework.transaction.support.TransactionTemplate.execute(T
ransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransa
ctionInterceptor.java:45)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterc
eptor.java:31)
        at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecu
torImpl.java:40)
        at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecu
torImpl.java:35)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.jav
a:168)
        at org.activiti.explorer.ui.task.TaskDetailPanel$5.buttonClick(TaskDetai
lPanel.java:353)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)

        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:164)
        at com.vaadin.ui.AbstractComponent.fireEvent(AbstractComponent.java:1219
)
        at com.vaadin.ui.Button.fireClick(Button.java:567)
        at com.vaadin.ui.Button.changeVariables(Button.java:223)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.changeVar
iables(AbstractCommunicationManager.java:1460)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVar
iableBurst(AbstractCommunicationManager.java:1404)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVar
iables(AbstractCommunicationManager.java:1329)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.doHandleU
idlRequest(AbstractCommunicationManager.java:761)
        at com.vaadin.terminal.gwt.server.CommunicationManager.handleUidlRequest
(CommunicationManager.java:325)
        at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(Abs
tractApplicationServlet.java:501)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:304)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:210)
        at org.activiti.explorer.filter.ExplorerFilter.doFilter(ExplorerFilter.j
ava:44)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:243)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:210)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:240)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:164)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(Authentica
torBase.java:462)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:164)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:100)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:
562)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:118)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:395)
        at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcesso
r.java:306)
        at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.pr
ocess(Http11AprProtocol.java:323)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:1719)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at java.lang.Thread.run(Thread.java:662)
Caused by: org.activiti.engine.ActivitiIllegalArgumentException: demo.tasklisten
er.DemoTaskListener doesn't implement interface org.activiti.engine.delegate.Tas
kListener
        at org.activiti.engine.impl.bpmn.helper.ClassDelegate.getTaskListenerIns
tance(ClassDelegate.java:106)
        at org.activiti.engine.impl.bpmn.helper.ClassDelegate.notify(ClassDelega
te.java:90)
        at org.activiti.engine.impl.delegate.TaskListenerInvocation.invoke(TaskL
istenerInvocation.java:34)
        at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(Delegate
Invocation.java:37)
        at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleIn
vocation(DefaultDelegateInterceptor.java:25)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.fireEvent(Task
Entity.java:549)
        … 49 more
12 Mar, 2014 11:52:17 AM com.vaadin.Application terminalError
SEVERE: Terminal error:
com.vaadin.event.ListenerMethod$MethodException: Invocation of method buttonClic
k in org.activiti.explorer.ui.task.TaskDetailPanel$5 failed.
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:530)

        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:164)
        at com.vaadin.ui.AbstractComponent.fireEvent(AbstractComponent.java:1219
)
        at com.vaadin.ui.Button.fireClick(Button.java:567)
        at com.vaadin.ui.Button.changeVariables(Button.java:223)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.changeVar
iables(AbstractCommunicationManager.java:1460)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVar
iableBurst(AbstractCommunicationManager.java:1404)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVar
iables(AbstractCommunicationManager.java:1329)
        at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.doHandleU
idlRequest(AbstractCommunicationManager.java:761)
        at com.vaadin.terminal.gwt.server.CommunicationManager.handleUidlRequest
(CommunicationManager.java:325)
        at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(Abs
tractApplicationServlet.java:501)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:304)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:210)
        at org.activiti.explorer.filter.ExplorerFilter.doFilter(ExplorerFilter.j
ava:44)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:243)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:210)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:240)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:164)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(Authentica
torBase.java:462)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:164)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:100)
        at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:
562)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:118)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:395)
        at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcesso
r.java:306)
        at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.pr
ocess(Http11AprProtocol.java:323)
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin
t.java:1719)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:908)
        at java.lang.Thread.run(Thread.java:662)
Caused by: org.activiti.engine.ActivitiException: Exception while invoking TaskL
istener: demo.tasklistener.DemoTaskListener doesn't implement interface org.acti
viti.engine.delegate.TaskListener
        at org.activiti.engine.impl.persistence.entity.TaskEntity.fireEvent(Task
Entity.java:553)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskE
ntity.java:146)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.
java:39)
        at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.
java:24)
        at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTa
skCmd.java:61)
        at org.activiti.engine.impl.interceptor.CommandInvoker.execute(CommandIn
voker.java:24)
        at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execut
e(CommandContextInterceptor.java:57)
        at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(Sp
ringTransactionInterceptor.java:47)
        at org.springframework.transaction.support.TransactionTemplate.execute(T
ransactionTemplate.java:130)
        at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransa
ctionInterceptor.java:45)
        at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterc
eptor.java:31)
        at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecu
torImpl.java:40)
        at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecu
torImpl.java:35)
        at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.jav
a:168)
        at org.activiti.explorer.ui.task.TaskDetailPanel$5.buttonClick(TaskDetai
lPanel.java:353)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)

        … 30 more
Caused by: org.activiti.engine.ActivitiIllegalArgumentException: demo.tasklisten
er.DemoTaskListener doesn't implement interface org.activiti.engine.delegate.Tas
kListener
        at org.activiti.engine.impl.bpmn.helper.ClassDelegate.getTaskListenerIns
tance(ClassDelegate.java:106)
        at org.activiti.engine.impl.bpmn.helper.ClassDelegate.notify(ClassDelega
te.java:90)
        at org.activiti.engine.impl.delegate.TaskListenerInvocation.invoke(TaskL
istenerInvocation.java:34)
        at org.activiti.engine.impl.delegate.DelegateInvocation.proceed(Delegate
Invocation.java:37)
        at org.activiti.engine.impl.delegate.DefaultDelegateInterceptor.handleIn
vocation(DefaultDelegateInterceptor.java:25)
        at org.activiti.engine.impl.persistence.entity.TaskEntity.fireEvent(Task
Entity.java:549)
        … 49 more


**>> I have put all jars that were told to put in tomcat lib also I added Vaadin jar in tomcat lib
3 REPLIES 3

martin_grofcik
Confirmed Champ
Confirmed Champ
Hi,


Caused by: org.activiti.engine.ActivitiException: Exception while invoking TaskListener: demo.tasklistener.DemoTaskListener doesn't implement interface org.activiti.engine.delegate.TaskListener

DemoTaskListener should implement TaskListener interface.

Regards
Martin

vijayd
Champ in-the-making
Champ in-the-making
Hi,
This is my class, you can see DemoTaskListener has implemented TaskListener interface :

package demo.tasklistener;

import org.activiti.engine.delegate.DelegateTask;
import org.activiti.engine.delegate.TaskListener;

public class DemoTaskListener implements TaskListener {

  private static final long serialVersionUID = 1L;

@Override
public void notify(DelegateTask arg0) {

  System.out.println("\n\n\n\t\t\tTaskListener Executed….\n\n\n");
}

}

martin_grofcik
Confirmed Champ
Confirmed Champ
Hi Vijay.
In that case you could follow existing working example and try to compare what  is different in yours… to find an error.
One example could be
org.activiti.engine.test.bpmn.usertask.UserTaskTest#testCompleteAfterParallelGateway

an activiti sources.
Regards
Martin