Hi All,
if any body will give some input on the following doubts will be highly appriciated .


I have created one processdefinition but i might left something any body can review it because it is deploying properly but while process was not starting and following error coming.:-
*************************************************************

java.lang.NullPointerException
 at org.jbpm.taskmgmt.exe.TaskMgmtInstance.instantiateNewTaskInstance(TaskMgmtInstance.java:177)Exception is java.lang.NullPointerException

*************************************************************

and processdefinition.xml is as follows:
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

<?xml version="1.0" encoding="UTF-8"?>

<process-definition name="Testing a process">

 <!-- SWIMLANES -->

 <swimlane name='B1'>
 <delegation class="com.test.hndlrs.assignment.B1AssignmentHandler">B1</delegation>
 </swimlane>

 <swimlane name='B2'>
 <delegation class="com.test.hndlrs.assignment.B2AssignmentHandler">B2</delegation>
 </swimlane>
 <swimlane name='B3'>
 <delegation class="com.test.hndlrs.assignment.B3AssignmentHandler">B3</delegation>
 </swimlane>
 <swimlane name='B4'>
 <delegation class="com.test.hndlrs.assignment.B4AssignmentHandler">B4</delegation>
 </swimlane>
 <swimlane name='B5'>
 <delegation class="com.test.hndlrs.assignment.B5AssignmentHandler">B5</delegation>
 </swimlane>

 <swimlane name='B6'>
 <delegation class="com.test.hndlrs.assignment.BRAssignmentHandler">B6</delegation>
 </swimlane>


 <!-- START-STATE -->
 <start-state name="Initiate Budget">
 <task swimlane="B1" />
 <transition to="Create a Plan"/>
 </start-state>

 <!-- NODES -->
 <task-node name="Create a Plan">
 <task name="Create a Plan" swimlane="B2"/>
 <transition name="bcat" to="Decision1"/>
 </task-node>

 <!-- DECISION -->
 <decision name="Decision1" >
 <handler class="com.test.hndlrs.decision.ApprovalBgt_cat_DecisionHandler" />
 <transition name="Hardware" to="ApprovalofB1" />
 <transition name="software" to="ApprovalofB2" />
 </decision>


 <task-node name="ApprovalofB1">
 <task name="ApprovalofB1" swimlane="B3"/>
 <transition name="abc1" to="DecisionApproval1"/>
 </task-node>

 <!-- DECISION -->
 <decision name="DecisionApproval1" >
 <handler class="com.test.hndlrs.decision.ApprovalBgtDecisionHandler" />
 <transition name="approve" to="Final Approve and Release Bgt Plan" />
 <transition name="disapprove" to="Revise Budget Plan" />
 </decision>


 <task-node name="ApprovalofB2">
 <task name="ApprovalofB2" swimlane="B4"/>
 <transition name="a1" to="DecisionApproval2"/>
 </task-node>

 <!-- DECISION -->
 <decision name="DecisionApproval2" >
 <handler class="com.test.hndlrs.decision.ApprovalBgtDecisionHandler" />
 <transition name="approve" to="Final Approve and Release Bgt Plan" />
 <transition name="disapprove" to="Revise Budget Plan" />
 </decision>

 <!-- NODES -->
 <task-node name="Final Approve and Release Bgt Plan">
 <task name="Final Approve and Release Bgt Plan" swimlane='B5' />
 <transition name="a3" to="done" />
 </task-node>
<!-- NODES -->
 <task-node name="Revise Budget Plan">
 <task name="Revise Budget Plan" swimlane='B6' />
 <transition name="a4" to="Final Approve and Release Bgt Plan" />
 </task-node>

 <!-- END-STATE -->
 <end-state name="done" />

</process-definition>

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Please give some input if any change required:
Code snippet i am trying to put is as follows:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

public void startProcess() {
 try {
 jbpmSession = jbpmSessionFactory.openJbpmSession();
 long processDefinitionId = ((ProcessDefinition)jbpmSession.getGraphSession().findLatestProcessDefinitions().get(0)).getId();
 jbpmSession.beginTransaction();
 ProcessDefinition processDefinition = jbpmSession.getGraphSession().loadProcessDefinition(processDefinitionId);
 ProcessInstance processInstance = new ProcessInstance(processDefinition);
 processInstance.getTaskMgmtInstance().createTaskInstance().setActorId("BI");
 processInstance.signal();
 jbpmSession.getGraphSession().saveProcessInstance(processInstance);
 jbpmSession.commitTransaction();
 LoggingInstance loggingInstance = processInstance.getLoggingInstance();
 List assignmentLogs = loggingInstance.getLogs(TaskAssignLog.class);
 System.out.println("assignmentlogs: "+assignmentLogs);
 if (assignmentLogs.size()==1) {
 TaskAssignLog taskAssignLog = (TaskAssignLog) assignmentLogs.get(0);
 System.out.println("A new task has been assigned to '"+taskAssignLog.getTaskNewActorId()+"'");
 }
 jbpmSession.close();
 } catch (Exception e) {
 System.out.println("Exception is "+e);
 e.printStackTrace();
 }
 }

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

Thanks & Regards,
Susant Patnaik