Processing Sound Library doesn't work

Processing Libraries
2

I think the problem is that you are trying to start the music at the wrong time.
Processing sketches have 3 different time periods: first one is initializing stuff, second one is everything that happens in setup(), and third is the draw() cycle.

It’s generally advised to initialize objects and do anything only inside of setup(), or draw() (or any other function that you define), but not in the initializing stage. I think that replacing your code with this should make it work:

import processing.sound.*;

SoundFile laserSound;
SoundFile music;

void setup(){
  laserSound = new SoundFile(this, "laser.mp3");
  music = new SoundFile(this, "music.mp3");
  music.play();
}