Today, I continued to implementing the experiments. Now, I finish a simple version of primary task, and the UI of the secondary task.
As I haven't got much experience in implementation of user interface, I learned how to use AWT and Java Swing for almost one day. The interface of my secondary task is not complicated, which has 20 radio buttons and two ordinary buttons for the subject to select the sum number of tones.
Additionally, Ronnie suggested use Java Swing instead of AWT. I think the reason maybe Swing is lightweight and independent of platforms.