public class Instrument implements Serializable
{


private List <Touche> listTouche;
private Timbre timbre;
private Image background;
private DisplayTouche disTouche;

private LoopPedal[] arrayLoopPedal;
private String name;
private Touche currentTouche;

private boolean playMode;
private SoundGenerator sGenerator;
}

public class SoundGenerator implements Serializable{
private Timbre timbre;
private transient Synthesizer synth;
private transient MidiChannel[] chan;
private transient Instrument[] inst;

/* public SoundGenerator()
{

} */

static final private int[] instValues = new int[]{33, 58, 25, 17, 112, 0, 80, 91};

public SoundGenerator(Timbre timbre) throws javax.sound.midi.MidiUnavailableException {
synth = MidiSystem.getSynthesizer();
synth.open();
chan = synth.getChannels();
try {
File bank = new File("src/Gaudrophone/domain/sound/soundbank.sf2");
inst = MidiSystem.getSoundbank(bank).getInstruments();
}
catch (InvalidMidiDataException | IOException exception) {
inst = synth.getDefaultSoundbank().getInstruments();
}
this.setTimbre(timbre);
}

public void setTimbre(Timbre timbre) {
chan[0].programChange(instValues[timbre.ordinal()]); /****************** null pointer exception here**********************/
}

public void generateSound(Sound sound) {
chan[0].noteOn(sound.getMidiNumber(), 200);
}

public void stopSound(Sound sound) {
chan[0].noteOff(sound.getMidiNumber());
}
}