JHarmony is a Java and Swing based standalone 100% Java application very useful for learning the basics of music theory.

It provides a nice userinterface which allows the user to learn the basic rules of cord-building and scale building.

all cords and scales can be played back instantly over MIDI.

A little MIDI keyboard based on a sample provided by Sun is included to make learning a little more fun.

This image shows the midi synthesizer section

This image shows the cord construction pane

  

Requirements: JDK 1.3 preinstalled ( can be found at www.javasoft.com) and for better playback quality install the sound bank provided in the SOUNDS section of the site mentionend above.