jbpm的问题，困扰了我好几天

[cruelsor]

跑一个流程，一到进行泳道分配时就出错了
- couldn't load delegation class 'jbpmservice.aAssignmentHandler'
java.lang.ClassNotFoundException: class 'jbpmservice.aAssignmentHandler' could not be found by the process classloader
- couldn't instantiate delegation class 'jbpmservice.aAssignmentHandler'
java.lang.NullPointerException
- Servlet.service() for servlet action threw exception
java.lang.NullPointerException
流程文件是：
<?xml version="1.0" encoding="UTF-8"?>

<process-definition xmlns="urn:jbpm.org:jpdl-3.1" name="accident">
<swimlane name="a" ><assignment class="jbpmservice.aAssignmentHandler" ></assignment>
</swimlane>
<swimlane name="b" ><assignment class="jbpmservice.bAssignment" ></assignment>
</swimlane>
<swimlane name="c" ><assignment class="jbpmservice.cAssignment"></assignment></swimlane>
<start-state name="start">
<transition name="报告事件" to="报告事件"></transition>
</start-state>
<task-node name="报告事件">

<task name="填写报告" swimlane="a">

<event type="task-start"><action class="src.jbpmaction.txbgaction"></action></event>
<controller>
<variable name="accid" access="read,write,require" mapped-name="accid" ></variable>
</controller>
</task>
<transition name="判断事件" to="判断事件"></transition><!--comment-->
</task-node>
<decision name="判断事件">
<handler class=""></handler>
<transition name="处理事件" to="处理事件" ></transition>
<transition name="受理处伤" to="受理处伤" ></transition>
</decision>
<task-node name="事件报告">
<task name="填写处理报告" swimlane="b">
<controller>
<variable name="accid" access="read,write,require" mapped-name="accid"></variable>
</controller>
</task>
<transition name="报批审批" to="报批审批"></transition>
</task-node>
<node name="处理事件">
<action name="Action_AccountantProcess" class=""></action>
<transition name="事件报告" to="事件报告"></transition>
</node>
<task-node name="报批审批">
<task name="审批" swimlane="c">
<controller>
<variable name="accid" access="read,write,require" mapped-name="accid"></variable>
</controller>
</task>
<transition name="end" to="end-state1"></transition>
</task-node>
<process-state name="受理处伤">
<sub-process name="hurt"></sub-process>
<transition name="处理事件" to="处理事件"></transition>
</process-state>
<end-state name="end-state1"></end-state>
</process-definition>
大家看看有没有问题啊，帮顶的也谢谢