Sometimes Eclipse keeps the changes it made to the files you edit. Does not always work but it's worth a try :
- Find you file in your (package, project, navigator) explorer.
- Right click on your file and look for the menus to compare... (I recommend Compare though in your case it will not matter since the file is now empty)
- Choose Local History... from the sub menu
If you are lucky and had been using Eclipse to edit the file you should find a few entries there. Look them up, chances are you will find the content.
This has helped me countless times and saved my ass on many occasions. However, every times I resort to it I always feel like hitting my head with a baseball bat for not commiting changes to the source control system earlier.
good luck, if that does not work I fear the SO will not be of much help to you :-(
--- EDIT ---
Little something that can help make this trick a tad bit more useful.
you can change the amount of information Eclipse keeps in local history, go to your preferences and then general->Workspace->Local History (Indigo here, may be different on other versions). If you tend to be light headed or burn the midnight oil a bit too much this will help you repair the next day that bug fix you insisted on finishing before going to sleep.
