声音崩溃客户端，如果用户没有声音

Question

您好，我正在向我的客户端添加声音，如果用户没有声音，则会崩溃客户端并出现此错误

    Exception in thread "Thread-3" java.lang.NullPointerException
 at Org.Game.Client.playMidi(Client.java:101)
 at Org.Game.Client.processOnDemandQueue(Client.java:3702)
 at Org.Game.Client.processGameLoop(Client.java:2959)
 at Org.Game.RSApplet.run(RSApplet.java:214)
 at Org.Game.Client.run(Client.java:5569)
 at java.lang.Thread.run(Unknown Source)

现在我想知道我怎样才能看到用户是否有声音，以及他们是否做不到这样就绕过了这个错误

public void playMidi(byte abyte0[]) {
    try {
        boolean quickSong = (prevSong > 0 ? true : false);
        boolean loopMusic = loop;
        if(midiPlayer.playing() && !quickSong){
            midiPlayer.play(abyte0, loopMusic, midiVolume);//add fading to this one
        }else{
            midiPlayer.play(abyte0, loopMusic, midiVolume);
        }
    }
}