Java and real-time audio "processing"

since I am a bit of a music enthusiast and I've been programming into Java for quite a bit I've had the idea of getting my hands into real-time audio processing/edititing/etc to learn a bit about it (hopefully).

My idea is to grab the input audio that comes from a connected microphone/eletric guitar/whatever plugged to the computer and play with it either adding some new "effects" or options to the sound itself, like something you'll do with a guitar/voice pedal but on a more modest level... for example a swing project with a few buttons to change the effects and a few bars to control the pitch, gain, bass, volume, bla bla.

So I would like to ask you for some info about this and if you think that it's something that is really HARD to do or if it's "doable" with Java. I've already been checking a bit about the sound API but I'm a bit lost so I hope you can give me a hand with some info.

Thanks.