#vulnerable code 
                                public ManagerResponse sendAction(ManagerAction action, long timeout)
            throws IOException, TimeoutException, IllegalArgumentException, IllegalStateException
    {
        ResponseHandlerResult result;
        SendActionCallback callbackHandler;

        result = new ResponseHandlerResult();
        callbackHandler = new DefaultSendActionCallback(result);

        synchronized (result)
        {
            sendAction(action, callbackHandler);

            // definitely return null for the response of user events
            if (action instanceof UserEventAction)
            {
                return null;
            }

            // only wait if we did not yet receive the response.
            // Responses may be returned really fast.
            if (result.getResponse() == null)
            {
                try
                {
                    result.wait(timeout);
                }
                catch (InterruptedException ex)
                {
                    logger.warn("Interrupted while waiting for result");
                    Thread.currentThread().interrupt();
                }
            }
        }

        // still no response?
        if (result.getResponse() == null)
        {
            throw new TimeoutException("Timeout waiting for response to " + action.getAction()
                    + (action.getActionId() == null ? "" : " (actionId: " + action.getActionId() + ")"));
        }

        return result.getResponse();
    } 
                            #location 12 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public ManagerResponse sendAction(ManagerAction action, long timeout)
            throws IOException, TimeoutException, IllegalArgumentException, IllegalStateException
    {
        ResponseHandlerResult result = new ResponseHandlerResult();
        SendActionCallback callbackHandler = new DefaultSendActionCallback(result);

        sendAction(action, callbackHandler);

        // definitely return null for the response of user events
        if (action instanceof UserEventAction)
        {
            return null;
        }

        // only wait if we did not yet receive the response.
        // Responses may be returned really fast.
        if (result.getResponse() == null)
        {
            try
            {
                result.await(timeout);
            }
            catch (InterruptedException ex)
            {
                logger.warn("Interrupted while waiting for result");
                Thread.currentThread().interrupt();
            }
        }

        // still no response?
        if (result.getResponse() == null)
        {
            throw new TimeoutException("Timeout waiting for response to " + action.getAction()
                    + (action.getActionId() == null ? "" : " (actionId: " + action.getActionId() + ")"));
        }

        return result.getResponse();
    }