Learning Java to do Android and learning Java to write large web and server applications for the enterprise are two completely different domains which just happ

Learning Java to do Android and learning Java to write large web and server applications for the enterprise are two completely different domains which just happen to share the same language. I think that one can learn the basics of Java to get started quickly, but the majority of one's time will be spent learning the intricacies of the SDKs and libraries. So the bigger question to ask yourself is whether you want to write mobile apps or enterprise apps. Pick one, and go from there. Don't worry about the language.