Control and LED with java.

Might seem trivial - you can turn a light on and off with a switch in practically every room you've been in in your life. But now you can control the flow of electricity with a Java program! You can program lights with a computer! And not only lights - since you can control the flow of electricity to a light, you can control the flow of electricity to motors, sensors, and more. You can build robots, automate your house, control cars, etc. using Java!