Not as much as a problem, but rather a question in the HeadFirst Midi player code

[Pedro Fonseca]

Ok, at first I typed everything just as in the book and...it didn't work, giving me a message that the Track symbol wasn't found.

import javax.sound.midi.*;

public class MiniMiniMusicApp {

  public static void main(String [] args) {
    MiniMiniMusicApp mini = new MiniMiniMusicApp();
    mini.play();
  }

  public void play() {

    try {
      Sequencer player = MidiSystem.getSequencer();
      player.open();
      Sequence seq = new Sequence(Sequence.PPQ, 4);
      Track track = seq.createTrack(); //Here's where things go bad

      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();

      Thread.sleep(2000);
      player.close();
      System.exit(0);

    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }
}

But much to my surprise, giving the full address of the Track object suddenly made everything work just fine!

[...]
    try {
      Sequencer player = MidiSystem.getSequencer();
      player.open();
      Sequence seq = new Sequence(Sequence.PPQ, 4);
      javax.sound.midi.Track track = seq.createTrack(); //Suddenly it works...why??
[...]

So I'm left wondering why in hell it didn't work previously, why didn't the import line work as intended? Is there any explanation at all?

[Campbell Ritchie]

Have you got a Track class of your own?

[Jeff Verdegan]

Your original version compiles fine for me. Most likely you changed something else, or weren't compiling that original code that you posted here.

[Jeff Verdegan]

Campbell Ritchie wrote:Have you got a Track class of your own?

That's what I thought too, but then it wouldn't give symbol not found for Track. I might complain about the method not being found, if his Track class doesn't have the same method.

Pedro Fonseca wrote:Ok, at first I typed everything just as in the book and...it didn't work, giving me a message that the Track symbol wasn't found.

@Pedro: Are you sure it was complaining that the class Track was not found? Not the method? Can you paste in the exact, complete error message?

[Pedro Fonseca]

Good catch, thanks for the replies.

Indeed the problem was another Track.class in the same folder as the MiniMiniMusicApp, I have to be more cautious about this sort of thing in the future.

[Campbell Ritchie]

Pedro Fonseca wrote:Good catch, thanks for the replies. . . .

You’re welcome We have seen this sort of thing before.