1. Why do you have raw .class files? Either you should have the source to compile them yourself, or they should be distributed within a jar file. Give the library author a slap and tell them to do a proper job.

If you need something straight away, I'd be inclined to jar them up yourself and reference that within your eclipse project.
2. Eclipse doesn't have a built-in GUI designer, but theres at least one good plug-in to do that, have a poke around the eclipse website for it.
(Who uses gui designers anyway?
Code generation is a design smell).
They were in jar files, it was me extracting them to folders, which I apparently should not do

Orangy, pls tell me this is a joke or a nigthmare, ppl write all the GUI code manually? Seriously, having 10-15 screens in a game would take months to write code for if not having any visual editor to place the components.
Seems to me like just a giant waste of time to place every little JButton, JLabel, JPanel and all the nasty gridbaglayout modifications manually.
By the way, I have now tested to import them as archive , the jar files I had. Now Eclipse find the com.jcraft.jogg and the com.jcraft.jorbis packages like intended but it does not find the .class files inside the jogg and jorbis lowest level folders so I get the same problem. Oh boy, should not importing .class files be easy to do without the compiler complaining for errors?