How can I compress an audio sample?

Question

Hi, I have raw audio sample in a byte array. I want to compress this sample. more specifically, I want to develop a method which will take this byte array as an input and returns the compressed sample in the byte array again. Please suggest me if anyone knows about this.
The code which I am using for capturing the data through the microphone is as follows. After executing the following, a byteArrayOutputStream is created, from which I am getting the captured audio byte array just by calling byteArrayOutputStream.toByteArray() method.
public void captureAudio(){
    try{
      //Get everything set up for
      // capture
      audioFormat = getAudioFormat();
      DataLine.Info dataLineInfo =
                new DataLine.Info(
                  TargetDataLine.class,
                   audioFormat);
      targetDataLine = (TargetDataLine)
                   AudioSystem.getLine(
                         dataLineInfo);
      targetDataLine.open(audioFormat);
      targetDataLine.start();
      //Create a thread to capture the
      // microphone data and start it
      // running.  It will run until
      // the Stop button is clicked.
      Thread captureThread =
                new Thread(
                  new CaptureThread());
      captureThread.start();
    } catch (Exception e) {
      System.out.println(e);
      System.exit(0);
    }//end catch
  }//end captureAudio method
class CaptureThread extends Thread{
  //An arbitrary-size temporary holding
  // buffer
  byte tempBuffer[] = new byte[10000];
  public void run(){
    byteArrayOutputStream =
           new ByteArrayOutputStream();
    stopCapture = false;
    try{//Loop until stopCapture is set
        // by another thread that
        // services the Stop button.
      while(!stopCapture){
        //Read data from the internal
        // buffer of the data line.
        int cnt = targetDataLine.read(
                    tempBuffer,
                    0,
                    tempBuffer.length);
        if(cnt > 0){
          //Save data in output stream
          // object.
          byteArrayOutputStream.write(
                   tempBuffer, 0, cnt);
        }//end if
      }//end while
      byteArrayOutputStream.close();
    }catch (Exception e) {
      System.out.println(e);
      System.exit(0);
    }//end catch
  }//end run
}//end inner class CaptureThreadI am new to sound api and I hope you got my question. Please ask me if anything required from my side.
Regards

Answer 1

Thanks Andrew and Captfoss, I agree both of you and I am really a newbie. Andrew, you are talking about the decreasing the quality, like what we do in video conferencing application where quality of an image not really matters [we set the jpeg quality to 0.5 etc]. I'll definitely do that. Please tell me the values for lower quality sound. The audio format I am using currently is as follows:
private AudioFormat getAudioFormat(){
    float sampleRate = 8000.0F;
    //8000,11025,16000,22050,44100
    int sampleSizeInBits = 16;
    //8,16
    int channels = 1;
    //1,2
    boolean signed = true;
    //true,false
    boolean bigEndian = false;
    //true,false
    return new AudioFormat(
                      sampleRate,
                      sampleSizeInBits,
                      channels,
                      signed,
                      bigEndian);
  }//end getAudioFormatcaptfoss, I also thought of ULAW compression. But I am not getting the way to apply this compression on the piece of sound which is stored in a byte[]. I am capturing the sound in piece by piece through the microphone.each piece of sound is stored in a byte[]. Now I want to compress this byte[] using ULAW. How can I do that? I don't have any file on the hard disk as I am capturing through the mic. Also, I don't want the compressed file to be stored on the hard disk. Instead, I'll want the compressed output in a byte[].