You can get by without having to learn much directly about Java - just by picking bits and pieces up as you need them. But the value in learning the underlying

You can get by without having to learn much directly about Java - just by picking bits and pieces up as you need them. But the value in learning the underlying platform, and indeed a key reason why these languages target the platform, is the wealth of libraries available. The question is really if it is worth writing your own libraries from scratch as opposed to learning and using the vast amount of (usually commercially-friendly licensed open source) code that is already out there. Most of the time this is a pretty simple choice.