title: Eclipse 4.3 Kepler missing JRE system library
body: <p>I am extremely new to java (about one week of experience at the moment). I have made a fair amount of simple programs in an older version of eclipse Juno on a PC. I copied all of the files onto a flash drive and put them into the workspace of eclipse kepler on my mac laptop. Now every single line of code is unrecognized and the JRE system library folder is gone from all of the projects. I am not sure how to fix this and I would love if someone will help my noob self at this. Thanks!</p>