public ClassDelegate createClassDelegateServiceTask(ServiceTask serviceTask) {
   Expression skipExpression;
   if (StringUtils.isNotEmpty(serviceTask.getSkipExpression())) {
     skipExpression = expressionManager.createExpression(serviceTask.getSkipExpression());
   } else {
     skipExpression = null;
   }
   return new ClassDelegate(
       serviceTask.getId(),
       serviceTask.getImplementation(),
       createFieldDeclarations(serviceTask.getFieldExtensions()),
       skipExpression,
       serviceTask.getMapExceptions());
 }
 public MailActivityBehavior createMailActivityBehavior(ServiceTask serviceTask) {
   return createMailActivityBehavior(serviceTask.getId(), serviceTask.getFieldExtensions());
 }