additional

   but when I start a process with processkey , variables and processInstancekey like this:

   

   executionService.startProcessInstanceByKey(processKey, variables, "abc");

  It report an exception:

 12:08:24,812 FIN | [TakeTransition] taking (start1)--to task1-->(task1)
### EXCEPTION ###########################################
12:08:24,828 INF | [DefaultCommandService] exception while executing command org.jbpm.pvm.internal.cmd.StartProcessInstanceInLatestCmd@b48b11
org.hibernate.ObjectNotFoundException: No row with the given identifier exists: [org.jbpm.jpdl.internal.model.JpdlExecution#0]
 at org.hibernate.impl.SessionFactoryImpl$1.handleEntityNotFound(SessionFactoryImpl.java:377)
 at org.hibernate.proxy.AbstractLazyInitializer.checkTargetState(AbstractLazyInitializer.java:79)
 at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:68)
 at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:111)
 at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150)
 at org.jbpm.jpdl.internal.model.JpdlExecution$$EnhancerByCGLIB$$da8329ee.createTask(<generated>)
 at org.jbpm.jpdl.internal.activity.TaskActivity.execute(TaskActivity.java:49)
 at org.jbpm.pvm.internal.model.op.ExecuteActivity.perform(ExecuteActivity.java:57)
 at org.jbpm.pvm.internal.model.ExecutionImpl.performAtomicOperationSync(ExecutionImpl.java:589)
 at org.jbpm.pvm.internal.model.ExecutionImpl.performAtomicOperation(ExecutionImpl.java:562)
 at org.jbpm.pvm.internal.model.ExecutionImpl.start(ExecutionImpl.java:201)
 at org.jbpm.pvm.internal.cmd.StartProcessInstanceInLatestCmd.execute(StartProcessInstanceInLatestCmd.java:63)
 at org.jbpm.pvm.internal.cmd.StartProcessInstanceInLatestCmd.execute(StartProcessInstanceInLatestCmd.java:39)
 at org.jbpm.pvm.internal.svc.DefaultCommandService.execute(DefaultCommandService.java:42)
 at org.jbpm.pvm.internal.tx.StandardTransactionInterceptor.execute(StandardTransactionInterceptor.java:54)
 at org.jbpm.pvm.internal.svc.EnvironmentInterceptor.execute(EnvironmentInterceptor.java:54)
 at org.jbpm.pvm.internal.svc.RetryInterceptor.execute(RetryInterceptor.java:55)
 at org.jbpm.pvm.internal.svc.ExecutionServiceImpl.startProcessInstanceByKey(ExecutionServiceImpl.java:80)

when i change my activity type from task to stat,  the exception does't appear.

So anybody know this case ?