Ubuntu – How to uninstall programs in ubuntu if they are not in Software Center? 12.04

try to uninstall it from terminal

sudo apt-get autoremove (app name)

and about this problem try to search in software sources may be you put repository broken or something like that and remove it from other software tab in software sources

and try this command may help you

1. sudo apt-get check

2. sudo apt-get update

3. sudo apt-get upgrade

4. sudo apt-get autoclean

5. sudo apt-get purge

and restart afte that try again

if not you can do that but i'm sure the won't help you but try it remove ubuntu software center by this command in terminal

sudo apt-get autoremove software-center

and return install it

sudo apt-get install software-center

To the best of my knowledge, Eclipse 4 is not currently (as of 12.04) available through the Ubuntu repositories and as a result you can't install it through the software center. However, as Eclipse runs contained within it's own directory, you should be able to just download Eclipse 4, extract it to a directory somewhere and run the IDE.

If you want a menu launcher for it, I would suggest searching for and installing "alacarte" (I believe it's called "Main Menu" in your apps list) in the software center. You can create a menu item manually for Eclipse with that app.