https://dl.dropboxusercontent.com/u/52666052/eclipse_mn.jpg
I’m like a wife who is so close to breaking up, but eclipse and I have children to think of…
[quote]Your pushing your luck eclipse…
[/quote]
twitches
This is a simple error caused by not having a JDK rt.jar on your build class path.
Cas 
That’s a nice .classpath file you have there. It’d be a shame if something were to happen to it…
That’s why I keep my .classpath file versioned. :cranky:
twitches
[/quote]
Argh, not intentionally 
Thing is with this, I didnt open the project for months and now it just stopped working
As if someone came in and removed the jdk over time >_>
Even then it doesnt work, gotta reinstall/update the android sdk apparently
Probably not relevant at all, but recently I updated my JDK. Last night I created a new WindowBuilder project (or class, WindowBuilder isn’t a type of project), and I had the same issues as you. Couldn’t find rt.jar, so I had to remove and re-add the Java System Library to the class path. First time that’s ever happened to me, I was surprised.