Socket programming Software using multi threading concepts

You may use open source code found on the Internet in your program. When citing this code: YOU MUST CITE THE EXACT URL TO THE CODE IN THE METHOD / FUNCTION / SUBROUTINE HEADER WHERE THE CODE IS UTILIZED. Your program must operate independently of a browser. Create file sharing between server and client 1. At most 3 clients 2. client must select Unique user names 3. client shall able to share file to server 4. Should not share file with same name 5. Accept the file from the client; 6. Print which file has been accepted from which client; 7. Notify the remaining clients that a new file is available; and, 8. Allow the remaining clients to retrieve the new file. 9. Everything must be done with GUI 10. There should be option to close connection other than closing GUI window directly. 11. Need exact Url of referred code. (After Clicking on that link, exact part code’s website.) 12. Comment for each function or loop describing what is that going to do.