Today I stumbled upon the problem eclipse did not find some classes with the code completition or [Ctrl-Shift-T]. If you write the class name in the code everything looks ok. I tried to clean my workspaces with rebuild etc. did not work.
But there is hope: After deleting all content in .metadata/.plugins/org.eclipse.jdt.core eclipse re-indexes the workspace again and everything is ok. I guess -clean as startup parameter would work likewise but I can’t verify.
Great tip! I was looking for a solution on this and this was really a time saver 😉 cheers