*/
public final IWorkItem claimWorkItem(String workItemId,
String taskInstanceId) throws EngineException, KernelException {
IPersistenceService persistenceService = rtCtx.getPersistenceService();
persistenceService.lockTaskInstance(taskInstanceId);
IWorkItem workItem = persistenceService.findWorkItemById(workItemId);
if (workItem == null)
return null;