I can't stop a AudioChannel filled up with a SineWave.

When I use AudioChannel.stop method, the program freezes ("loop" stops being printed).

2. import processing.core.PApplet;
3. import krister.Ess.AudioChannel;
4. import krister.Ess.Ess;
5. import krister.Ess.SineWave;
6. 
   
7. public class TestApplet extends PApplet {
8.     AudioChannel myChannel;
9.     SineWave wave;
10. 
    
11.     public void setup() {
12.         size(256,200);
13.         Ess.start(this);
14. 
    
15.         myChannel = new AudioChannel();
16.         myChannel.initChannel(myChannel.frames(100));
17.         wave = new SineWave(400, 1f);
18.         wave.generate(myChannel);
19. 
    
20.         myChannel.play(Ess.FOREVER);
21.     }
22. 
    
23.     public void draw() {
24.         println("loop"); 
25.     }
26. 
    
27.     public void keyPressed() {
28.         if (myChannel.state == Ess.STOPPED)
29.             myChannel.play();
30.         else
31.             myChannel.stop();
32.     }
33. 
    
34.     public void stop() {
35.         Ess.stop();
36.         super.stop();
37.     }
38. }

How can I fix that?