Recently I have been asked to do a web-based login and register system using JAVA. But I haven't learnt java before and had absolutely no idea how java works or to write java codes. They told me that I have to learn Java quickly as possible. Currently looking some java stuff on the internet. Honestly, my head spins when i look at the codes. However, I do know PHP(intermediate level)(wihtout OOP). Really having a hard times learning java. How long will it take normally to learn java? Is it worth to learn java instead of PHP?