If its a headless machine change "-cp" to "-classpath" and change every instance of a ";" to a ":".
If its a normal machine, open up a termnal by typing "ctrl+alt+t" and type the command "sudo apt-get install eclipse". After you are done typeing the "e" hit "tab" a few times to see all available packages. That will install eclipse and then you can you server/client just like normal.
also i woudl change 800 to either 1024 or 512