the idea (or at least the most common result) of the AP tests are to give one college credit for knowledge one has gained prior to attending such an institution. Therefore, they would try to replicate the knowledge set most commonly related in college, most notably the coding portion. Intro comp sci courses involve coding, so therefore the AP's do as well. Ideally just knowledge of the basic concepts would be worthwhile, but the AP's are bound by what the colleges teach, so they must cover the java