Eclipse deleted all my project

Directly in Eclipse does not. To recover you need to undelete the files. To do this immediately turn off your computer, better if you go directly to the button without going on the shutdown, remove your HD from inside the computer and place as slave (secondary HD) on another machine. Once done use one of the many existing undelete software. The above steps are necessary because the space of the files once made available to S.O. can be rewritten with something else. The more operations you do, the more likely your files will be overwritten. The main hd is usually heavily etched with the normal activities of the S. O. so the need to place as a slave before beginning the undelete procedure. Also if project is large the likelihood of recovery of all files decreases.