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I am trying to make a music player in java. I have gone to numerous websites and looked at resources to see how it works, but AudioInputStream gives me a nullPointerException in a place where I least expect it! It seems that no one has asked this question before (in addition, I don't have enough rep to comment so I had to make this a separate question), so I'll show you the code where it's going wrong:

Clip clip = AudioSystem.getClip();
AudioInputStream ais = AudioSystem.getInputStream(new File("mywav.wav"));
clip.open(ais);
clip.start();

I surrounded this with Thread and started the Thread, so it should play fully. But, I get a nullPointerException at the line "AudioInputStream ais = AudioSystem.getInputStream(...."

Patrick
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Ashok
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2 Answers2

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1) You can load your sound from where-ever. A folder called "sound" is just a convenience, such as a folder called "images" for your art graphics.

2) I think you will have better luck if you use the URL instead of the file as your input source.

Thus:

URL url = this.getClass().getResource("mywav.wav");
AudioInputStream aiStream = AudioSystem.getAudioInputStream(url);

One obscure problem that comes up (and I've helped about a dozen people making the same error) is that when you do it your way, you create the intermediate step where there is an InputStream. If you check the JavaDocs for AudioSystem.getAudioInputStream(url) vs AudioSystem.getAudioInputStream(inputStream), you will see that the InputStream has to be a "markable" file, and there are no guarantees of this. With the URL form, there is no such test or requirement.

Here are the links, for easier perusal. http://docs.oracle.com/javase/6/docs/api/javax/sound/sampled/AudioSystem.html#getAudioInputStream(java.net.URL) http://docs.oracle.com/javase/6/docs/api/javax/sound/sampled/AudioSystem.html#getAudioInputStream(java.io.InputStream)

It seems prior to Java 7, for some reason, there was a default such that the system "knew" how to handle wav files, but this default is no longer in place and many folks who used your way of getting their AudioInputStream from an InputStream suddenly found their sound code broken. There's even an offical Oracle bug report on this: #7095006

Phil Freihofner
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  • It's still giving me a nullPointer exception when initializing the AudioInputStream. :( – Ashok Nov 28 '12 at 16:48
  • Problem solved! What I did was use the roundabout method that Phil was talking about. I read up on InputStreams and used a reader to read the song through and put it into an AudioInputStream. Thanks everyone! – Ashok Nov 28 '12 at 16:54
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Try this instead

private AudioClip clip;
clip = getAudioClip(getCodeBase(), "sounds/mywav.wav");
clip.loop();

You will need to create a new folder called sounds. Then put your sound file, in the folder. Note that all your sounds have to be .wav

java
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