How to get video and audio streams from web cameras with Java?

With java media framework JMF or FMJ

Here is an example with JVM

I see your comment about the solution needing to be "pure" java, but this is really "nearly" impossible. You will need to use some sort of native library for accessing the devices, with that being stated; I suggest that you look at Xuggler as your solution. Xuggler supports Windows, Mac, and Linux and they also offer example code for handling audio and video. Lastly the library is FREE. Webcam capture example: http://xuggle.googlecode.com/svn/trunk/java/xuggle-xuggler/src/com/xuggle/xuggler/demos/DisplayWebcamVideo.java

While Xuggle does not have an example of microphone capture, you can find samples on the mailing list or you could use code written by the packet-mulitbroadcaster project found here: https://code.google.com/p/packet-multibroadcaster/