1. When a client requests a data operation, your javabean stores the request in a file, and then you can return a response to the client.
2. Make your own application program, a thread, that listens to that file (or a directory) at intervals, and if it finds a new file, reads it, and performs a long operation as requested. When the operation is finished, update a flag A (either in the database or in the file) and remove the file (to avoid repeating the operation on this file).
3. Customers will always refresh the page or send a new page request from time to time, this time to check the flag A, if completed, on the page to prompt the user, such as msdn's "you have a short message"