I understand that this is a relatively common question, but I've followed the answers to so many of these at this point and none of them work.
I'm using Eclipse (on Mac now although I had the issue on Windows) and I want to learn the LWJGL which is a library for Java. I downloaded all the jars, and copied them into a lib folder:

then, as an example I added 3 of them to the project's build path, so that they appear in the referenced libraries section
Now, although I can literally see that org.lwjgl for example is in my referenced libraries, I am always unable to use it in my code...
does anyone know why this keeps happening?


