public String execute(CommandContext commandContext) {
ProcessDefinitionManager processDefinitionManager = commandContext.getProcessDefinitionManager();
ProcessDefinitionBehavior processDefinition = processDefinitionManager
.findLatestProcessDefinitionById(processDefinitionId);
UserTaskBehavior userTask = (UserTaskBehavior) processDefinition.getDefinitions().getElement(nodeId);
Object returnFormUri = null;
if(userTask.getFormUri()!=null && !userTask.getFormUri().equals(""))
returnFormUri=ExpressionMgmt.execute(userTask.getFormUri(),processDefinition);