code: @Deployment public void testChangeFormKey(){
    ProcessInstance processInstance=runtimeService.startProcessInstanceByKey("dynamicUserTask");
    String processDefinitionId=processInstance.getProcessDefinitionId();
    Task task=taskService.createTaskQuery().processInstanceId(processInstance.getId()).singleResult();
    assertEquals("test",task.getFormKey());
    taskService.complete(task.getId());
    assertProcessEnded(processInstance.getId());
    ObjectNode infoNode=dynamicBpmnService.changeUserTaskFormKey("task1","test2");
    dynamicBpmnService.saveProcessDefinitionInfo(processDefinitionId,infoNode);
    processInstance=runtimeService.startProcessInstanceByKey("dynamicUserTask");
    task=taskService.createTaskQuery().processInstanceId(processInstance.getId()).singleResult();
    assertEquals("test",task.getFormKey());
    taskService.complete(task.getId());
    assertProcessEnded(processInstance.getId());
  }
  