midi player when used from commandline does not work

[Jonathan Miltner]

hi i am trying to work my way through the head first book but for some reason the midi player does not work right on my mac os X

right now all i want is to at least figure out how to make sound dynamically. so i found this source code based on the book which makes a sound but doesnt exit right:

import javax.sound.midi.*;
 
public class MiniMiniMusicApp {
 
public static void main(String[] args){
MiniMiniMusicApp mini = new MiniMiniMusicApp();
mini.play();
System.out.println("Competed Main");
}
 
public void play() {
 
try {
Sequencer player = MidiSystem.getSequencer();
player.open();
 
Sequence seq = new Sequence(Sequence.PPQ, 4);
 
Track track = seq.createTrack();
 
ShortMessage a = new ShortMessage();
a.setMessage(144,1,44,100);
MidiEvent noteOn = new MidiEvent(a,1);
track.add(noteOn);
 
ShortMessage b = new ShortMessage();
b.setMessage(128,1,44,100);
MidiEvent noteOff = new MidiEvent(b,16);
track.add(noteOff);
 
player.setSequence(seq);
 
player.start();
 
} catch (Exception ex) {
ex.printStackTrace();
}
System.out.println("Competed Play");
}
}

[BOLD] but here is the real problem:[/BOLD]
when i try to modify it to take the note command from the command line as below. nothing works...
please helpppppp!!!

new code:

package midi;
 
import javax.sound.midi.*;
 
public class MiniMiniMusicApp {
 
 public static void main(String[] args){
 
 MiniMiniMusicApp mini = new MiniMiniMusicApp();
 
 if (args.length < 1) {
System.out.println("note required");
System.exit(0);
} else {
int note = Integer.parseInt(args[0]);
System.out.println("playing: "  + note);
 
 mini.play(note);
 System.out.println("Competed Main");
 System.exit(0);
 }
 }
 
 public void play(int note) {
 
 try {
 Sequencer player = MidiSystem.getSequencer();
 player.open();
 
 Sequence seq = new Sequence(Sequence.PPQ, 4);
 
 Track track = seq.createTrack();
 
 ShortMessage a = new ShortMessage();
 System.out.println("setting note for message a to: " + note);
 a.setMessage(144,1,note,100);
 MidiEvent noteOn = new MidiEvent(a,1);
 track.add(noteOn);
 
 ShortMessage b = new ShortMessage();
 System.out.println("setting note for message b to: " + note);
 b.setMessage(128,1,note,100);
 MidiEvent noteOff = new MidiEvent(b,16);
 track.add(noteOff);
 
 player.setSequence(seq);
 
 player.start();
 
 } catch (Exception ex) {
 ex.printStackTrace();
 }
 System.out.println("Competed Play");
 }
} 

[Lando Chan]

I experienced the same problem but it has been solved. Try to increase the volume, I did not hear the sound at first.