Need help to stop audio from playing after called method

I’ve made a launcher for a game with background music, and when I press a button to start the game I want to stop the music from playing. I’ve tried doing this by calling the method “quit” where I told the music player to stop playing, but it isn’t working, please help!

 public class LauncherSound implements Runnable
{

private static ArrayList<String> launchersound;
private int currentSongIndex;
public static FloatControl gainControl;
public static Clip clip;

public LauncherSound(String... files)
{
    launchersound = new ArrayList<String>();
    for(String file : files)
        launchersound.add("./resources/audio/launcher/" + file + ".wav");       
}
private void playSound(String launchersound)
{
    try 
    {
        File soundFile = new File(launchersound);
        AudioInputStream ais = AudioSystem.getAudioInputStream(soundFile);
        AudioFormat format = ais.getFormat();
        DataLine.Info info = new DataLine.Info(Clip.class, format);
        clip = (Clip) AudioSystem.getLine(info);
        clip.open(ais);
        gainControl = (FloatControl) 
clip.getControl(FloatControl.Type.MASTER_GAIN);
        gainControl.setValue(-5);
        clip.start();

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


public void run()
{
    playSound(launchersound.get(currentSongIndex));
}

public static void stop() 
{
    clip.close();
    clip.stop();
}
}