Java does not play a particular .au file, while other tools on Solaris do playing it.

Testcase
--------
The original wakeup.au is attached to this bugreport.

# /usr/bin/audioplay wakeup.au
=> You hear the sound.

# /usr/dt/bin/sdtaudio wakeup.au
=> You hear the sound.

Now, try to play it with Java. Use the following source and compile it.

// begin source
// test case from the Java Developer Almanach, Addison Wesley
// http://javaalmanac.com/egs/javax.sound.sampled/Load.html

import java.io.*;
import javax.sound.sampled.*;

public class Jplay {

  public static void main(String[] args) {
      if (args.length < 1) {
        System.out.println("java Jplay audiofile");
        System.exit(0);
      }
      new Jplay(args[0]);
  }

  public void printFormat(AudioFormat format) {
      System.out.println("Encoding: "+format.getEncoding());
      System.out.println("SampleRate: "+format.getSampleRate());
      System.out.println("SampleSizeInBits: "+format.getSampleSizeInBits());
      System.out.println("Channels: "+format.getChannels());
      System.out.println("FrameSize: "+format.getFrameSize());
      System.out.println("FrameRate: "+format.getFrameRate());
  }

  public Jplay(String sound) {
    try {

      AudioInputStream stream = AudioSystem.getAudioInputStream(new File(sound));
    
      // At present, ALAW and ULAW encodings must be converted
      // to PCM_SIGNED before it can be played
      AudioFormat format = stream.getFormat();
      System.out.println("Stream:");
      printFormat(format);

      if (format.getEncoding() != AudioFormat.Encoding.PCM_SIGNED) {
          format = new AudioFormat(
                   AudioFormat.Encoding.PCM_SIGNED,
                   format.getSampleRate(),
                   format.getSampleSizeInBits()*2,
                   format.getChannels(),
                   format.getFrameSize()*2,
                   format.getFrameRate(),
                   true); // big endian
           stream = AudioSystem.getAudioInputStream(format, stream);
           System.out.println("\nConverted stream:");
           printFormat(format);
      }
    
      DataLine.Info info = new DataLine.Info(
         Clip.class, stream.getFormat(), ((int)stream.getFrameLength()*format.getFrameSize()));
      Clip clip = (Clip) AudioSystem.getLine(info);

      // Add a listener for line events
      clip.addLineListener(new LineListener() {
        public void update(LineEvent evt) {
            if (evt.getType() == LineEvent.Type.STOP) {
               System.out.println("Sound stopped.");
               System.exit(0);
            }
        }
      });

      System.out.println("Playing sound...");
      clip.open(stream);
      clip.start();
      
   } catch (IOException e) {
     System.err.println(e);
   } catch (LineUnavailableException e) {
     System.err.println(e);
   } catch (UnsupportedAudioFileException e) {
     System.err.println(e);
   }
  }
}
// end source

# java -version
java version "1.4.2_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_04-b05)
Java HotSpot(TM) Client VM (build 1.4.2_04-b05, mixed mode)

(I've also tried build 1.5.0-beta2-b44, but I got the same results)

# java Jplay wakeup.au
Stream:
Encoding: ULAW
SampleRate: 8000.0
SampleSizeInBits: 8
Channels: 1
FrameSize: 1
FrameRate: 8000.0

Converted stream:
Encoding: PCM_SIGNED
SampleRate: 8000.0
SampleSizeInBits: 16
Channels: 1
FrameSize: 2
FrameRate: 8000.0
Exception in thread "main" java.lang.IllegalArgumentException: No line matching interface Clip supporting format PCM_SIGNED, 8000.0 Hz, 16 bit, mono, big-endian, audio data, and buffers of -2 to -2 bytes is supported.
        at javax.sound.sampled.AudioSystem.getLine(AudioSystem.java:339)
        at Jplay.<init>(Jplay.java:50)
        at Jplay.main(Jplay.java:11)

=> You don't hear the sound. The original .au can not be played by using Java, but it can be played using other tools. In Java you get an IllegalArgumentException.