NullPointerException with task assignment

[tobysaville]

When i execute the following JUnit Test Case:

 public void testTaskAssignment(){

 ProcessDefinition processDefinition = ProcessDefinition.parseXmlString(
 "<process-definition name='the baby process'>" +
 " <start-state>" +
 " <transition name='baby cries' to='t' />" +
 " </start-state>" +
 " <task-node name='t'>" +
 " <transition to='end' />" +
 " </task-node>" +
 " <end-state name='end' />" +
 "</process-definition>"
 );

 ProcessInstance processInstance = new ProcessInstance(processDefinition);

 Token token = processInstance.getRootToken();

 token.signal();

 try{
 TaskInstance tInstance = (TaskInstance) processInstance.
 getTaskMgmtInstance().
 getTaskInstances().
 iterator().
 next();

 tInstance.end();
 }catch(NullPointerException npe){
 System.out.println("No tasks");
 }
 }

Everything works ok (there are no task instances, but thats ok). However, when i add the following lines to the process definition XML:

" <task name='change nappy'>" +
" <assignment class='com.test.MyAssigHandler' />" +
" </task>" +

I get the following exception:

java.lang.NullPointerException
 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at org.jbpm.instantiation.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:16)
 at org.jbpm.taskmgmt.exe.TaskMgmtInstance.getTaskInstanceClass(TaskMgmtInstance.java:41)
 at org.jbpm.taskmgmt.exe.TaskMgmtInstance.instantiateNewTaskInstance(TaskMgmtInstance.java:174)
 at org.jbpm.taskmgmt.exe.TaskMgmtInstance.createTaskInstance(TaskMgmtInstance.java:74)
 at org.jbpm.graph.node.TaskNode.execute(TaskNode.java:136)
 at org.jbpm.graph.def.Node.enter(Node.java:284)
 at org.jbpm.graph.def.Transition.take(Transition.java:92)
 at org.jbpm.graph.def.Node.leave(Node.java:349)
 at org.jbpm.graph.node.StartState.leave(StartState.java:73)
 at org.jbpm.graph.exe.Token.signal(Token.java:127)
 at org.jbpm.graph.exe.Token.signal(Token.java:92)
 at com.qas.newmedia.intranet.oem.test.TestTaskAssignment.testTaskAssignment(TestTaskAssignment.java:32)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
 at java.lang.reflect.Method.invoke(Unknown Source)
 at junit.framework.TestCase.runTest(TestCase.java:154)
 at junit.framework.TestCase.runBare(TestCase.java:127)
 at junit.framework.TestResult$1.protect(TestResult.java:106)
 at junit.framework.TestResult.runProtected(TestResult.java:124)
 at junit.framework.TestResult.run(TestResult.java:109)
 at junit.framework.TestCase.run(TestCase.java:118)
 at junit.framework.TestSuite.runTest(TestSuite.java:208)
 at junit.framework.TestSuite.run(TestSuite.java:203)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:478)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:344)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)

The NullPointer is raised when on the line that i call

token.signal();

Is there any reason this might be?

Thanks,

toby

[tobysaville]

Incase anyone comes across this problem, this is the answer:

You need to add the following line to your jbm.properties file:

jbpm.task.instance.class=org.jbpm.taskmgmt.exe.TaskInstance

It couldnt find the class definition to use as a TaskInstance. The doco says there is a default, but if there is no declaration in the properties file, it throws a NullPointerException in the ClassLoaderUtil class when trying to load class with a null name value (called from TaskMgmtInstance on line 41)

toby

[kukeltje]

afaik there is aq default IF the jbpm.taskinstance.class property is not in the config. If it is and it has no value yes... then I can imagine the NPE (should be caught btw)