While p5ee and j2ee both have two letter "E"s in them, there really isn't any similarity. when you use j2ee you get a significant amount of functionality for free and without any development cost. j2ee has full transaction support... distributed even. The j2ee automatic persistence model (CMP) is powerful and basically a walk in the park to use. When CMP isn't enough, it's just as trivial to create your own persistence model (BMP). I had hope p5ee would be this, but it seems to be heading in a different direction. I wish the p5ee project would take note of this. Otherwise, in the end, p5ee makes it into corporate use (thanks to unintelligent man agers perhaps) merely based on j2ee's good name.