I have a "could not initialize proxy" exception in a workflow when I try to get the process definition id from tasks which are between a fork and a join. The problem doesn't occur if I have not a split/join implementation.

Process Definition:

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

<process key="id" name="id" xmlns="http://jbpm.org/4.0/jpdl">
 <start g="123,34,32,29" name="start1">
 <transition to="fork2"/>
 </start>
 <end g="137,339,120,108" name="end1"/>
 <join g="-52,68,42,30" name="join1"/>
 <fork g="126,108,46,26" name="fork2">
 <transition to="task1"/>
 <transition to="task2"/>
 </fork>
 <task assignee="test" g="70,189,71,53" name="task1">
 <transition to="join2"/>
 </task>
 <task assignee="test" g="167,189,83,49" name="task2">
 <transition to="join2"/>
 </task>
 <join g="136,262,58,45" name="join2">
 <transition to="end1"/>
 </join>
</process>

Test case:

package org.jbpm.examples.processdefinition.id;

import java.util.List;
import org.jbpm.api.Execution;
import org.jbpm.api.ProcessInstance;
import org.jbpm.api.task.Task;
import org.jbpm.test.JbpmTestCase;

/**
 * @author David Loiseau
 */

public class ProcessDefinitionIdTest extends JbpmTestCase {


 String deploymentId;

 protected void setUp() throws Exception {
 super.setUp();

 deploymentId = repositoryService.createDeployment()
 .addResourceFromClasspath("org/jbpm/examples/processdefinition/id/process.jpdl.xml")
 .deploy();
 }

 public void testFindProcessDefinitionIdFromExecution(){
 String actorName = "test";
 ProcessInstance processInstance = executionService.startProcessInstanceByKey("id");
 List<Task> tasks = taskService.findPersonalTasks(actorName);
 for(Task task : tasks){
 Execution execution = processEngine.getExecutionService().findExecutionById(task.getExecutionId());
 String processDefinitionId = execution.getProcessInstance().getProcessDefinitionId();
 assertNotNull(processDefinitionId);
 }
 }

 protected void tearDown() throws Exception {
 repositoryService.deleteDeploymentCascade(deploymentId);

 super.tearDown();
 }


}

Exception:

### EXCEPTION ###########################################
17:26:39,203 SEV | [BaseJbpmTestCase] TEST THROWS EXCEPTION: could not initialize proxy - no Session
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
 at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:86)
 at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:140)
 at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190)
 at org.jbpm.pvm.internal.model.ExecutionImpl_$$_javassist_4.getProcessDefinitionId(ExecutionImpl_$$_javassist_4.java)
 at org.jbpm.examples.processdefinition.id.ProcessDefinitionIdTest.testFindProcessDefinitionIdFromExecution(ProcessDefinitionIdTest.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:164)
 at org.jbpm.test.BaseJbpmTestCase.runTest(BaseJbpmTestCase.java:80)
 at junit.framework.TestCase.runBare(TestCase.java:130)
 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:120)
 at junit.framework.TestSuite.runTest(TestSuite.java:230)
 at junit.framework.TestSuite.run(TestSuite.java:225)
 at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:79)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
### EXCEPTION ###########################################