Hello, i am wondering if someone could help me break this code down and teach me what it does/how it works. the code i know is a background on a java client, its a skybox of sorts and is a panorama, i want to change it to a stationary background. the code is as follows

Code:
http://www.megaupload.com/?d=PR6WD7QN
something in the code was getting flagged by the spamfilter so i uploaded a txt file instead.