Java EE (Java Enterprise Edition) General Discussion

Hi
Thank you for reading my post.
I have an application which shuld consume message of a queue.
my application is multithread and what i want to know is:

- How i can ask queue to remove a message after my thread finished its work with the message, by this way i can ensure that if my thread face an exception after it read the message my message will not lose.

- As it is multithread application, How i can ensure that a message is not delivered to two or more thread? is there any way to consume the messages in a synchronized way?

Will synchronized access restrict the performance?

Thanks