First off, 48h is a tough call - the JVM is a huge ecosystem! You might want to moderate your expectations. Personal suggestions would be: - Get one of the ma

First off, 48h is a tough call - the JVM is a huge ecosystem! You might want to moderate your expectations. Personal suggestions would be: - Get one of the major open source IDEs. I personally recommend Eclipse (http://www.eclipse.org/ http://www.eclipse.org/) - Learn some Java first. Since it's the Ligua France on the JVM, you'll want to know it if only so you can read code. If you like your more modern languages you can always switch to Scala/Clojure later once you are familiar with the Java ecosystem. - Play (http://www.playframework.org/ http://www.playframework.org/) is a great framework for your web app. Give it a try. - Netty is a great IO framework (http://netty.io/ http://netty.io/). If you really care about IO performance, you will probably want to use Netty (or something based on Netty). I've used Netty for low-latency game servers, for example.