播放midi文件会返回错误

Question

我写了一个类来播放midi文件。我已经通过在自己的线程中运行它来测试这个类，它播放的是预期的歌曲，但它也会以红色显示警告：

May 21, 2014 12:55:03 PM java.util.prefs.WindowsPreferences <init>
WARNING: Could not open/create prefs root node Software\JavaSoft\Prefs at root 0x80000002. Windows RegCreateKeyEx(...) returned error code 5.

我的代码有效，但我想知道这个警告意味着什么，以及如何修复它。

public class MusicBox implements Runnable {

    private Sequence midi;
    private Sequencer sequencer;
    private boolean playSong;

    public MusicBox() {

        try {
            this.midi = MidiSystem.getSequence(new File("src//BennyHill.mid"));
            this.sequencer = MidiSystem.getSequencer();
        } catch (InvalidMidiDataException e) {
            System.out.println("invalidMidiData exception in Music Box");
            e.printStackTrace();
    } catch (IOException e){
            System.out.println("IO exception in Music Box");
            e.printStackTrace();            
        } catch (MidiUnavailableException e) {
            System.out.println("Midi Unavailable Exception in Music Box");
            e.printStackTrace();
        }   
            this.playSong = false;
    }

    @Override
    public void run() {

        try {
            this.sequencer.open();
            this.sequencer.setSequence(this.midi);
        } catch (MidiUnavailableException e) {
            System.out.println("MidiUnavailableException in play music (run)");
            e.printStackTrace();
        } catch (InvalidMidiDataException e) {
            System.out.println("InvalidMidiDataException in play music (run)");
            e.printStackTrace();
        }

        this.sequencer.start();

        while(this.playSong){
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                 //do nothing
            }
        }
        this.sequencer.stop();
        this.sequencer.close();
    }
}