Threading Issue

Question

I am have written a test app in swing. The test app has two buttons and a progressbar. When I click the stop button, the stopButtonMouseClicked method is called, but the loop does not always terminate in the signalReader thread. Does anyone have any insight into this? A variable named "running" is set to true at the top of the loop, and is set to false when the stopButtonMouseClicked method is called.
The code that starts and stops my thread is:
private void buttonMouseClicked(MouseEvent evt){
signalReader = new SignalReader(dataLine, progressBar);
signalReader.startRecording();
private void stopButtonMouseClicked(MouseEvent evt){     
signalReader.stopRecording();
The class that extends Thread follows:
package swing;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.TargetDataLine;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
/** Data is moved from the target line to the output stream. */
class SignalReader extends Thread {
     public SignalReader(TargetDataLine dataLine, JProgressBar progressBar) {
          this.dataLine = dataLine;
          this.outputStream = new ByteArrayOutputStream();
          this.progressBar = progressBar;
          AudioFormat audioFormat = dataLine.getFormat();
          int bufferSize = (int) audioFormat.getSampleRate() * audioFormat.getFrameSize();
          buffer = new byte[ bufferSize ];
public void startRecording() {
// Start moving data.
     dataLine.start();
     super.start();
public void stopRecording() {
     // Stops data line I/O when the buffer is drained.
     dataLine.drain();
     // Free the resources the line has obtained.
     dataLine.close();
     running = false;
     try {
     outputStream.close();
     } catch ( IOException e ) {
     e.printStackTrace();
// Thread processing
public void run() {
running = true;
while ( running ) {
     // Move data from the target line (input)to the buffer (output).
     int bytesRead = dataLine.read( buffer, 0, buffer.length );
final int audioLevel = findAudioLevel(buffer);
progressBar.setValue(audioLevel);
System.out.println("Calculated audio level: " + audioLevel);
     if ( bytesRead >= 0 ){
     outputStream.write( buffer, 0, bytesRead );
public int findAudioLevel(byte theAudioData[])
//Do some audio calculations
// Fields
protected TargetDataLine dataLine;
protected ByteArrayOutputStream outputStream;
protected boolean running;
protected byte [] buffer;
static int WAV_HEADER_SIZE = 44;
protected JProgressBar progressBar;
}

Answer 1

The code that starts and stops my thread is:
private void buttonMouseClicked(MouseEvent evt){
signalReader = new SignalReader(dataLine, progressBar);
signalReader.startRecording();
private void stopButtonMouseClicked(MouseEvent evt){
signalReader.stopRecording();
}The class that extends Thread follows:
package swing;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.TargetDataLine;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
/** Data is moved from the target line to the output stream. */
class SignalReader extends Thread {
      public SignalReader(TargetDataLine dataLine, JProgressBar progressBar) {
            this.dataLine = dataLine;
            this.outputStream = new ByteArrayOutputStream();
            this.progressBar = progressBar;
            AudioFormat audioFormat = dataLine.getFormat();
            int bufferSize = (int) audioFormat.getSampleRate() * audioFormat.getFrameSize();
            buffer = new byte[ bufferSize ];
public void startRecording() {
  // Start moving data.
       dataLine.start();
       super.start();
public void stopRecording() {
       // Stops data line I/O when the buffer is drained.
       dataLine.drain();
       // Free the resources the line has obtained.
       dataLine.close();
       running = false;
       System.out.println("SignalReader - stopRecording!");
       try {
           outputStream.close();
       } catch ( IOException e ) {
           e.printStackTrace();
// Thread processing
public void run() {
  running = true;
  while ( running ) {
       // Move data from the target line (input)to the buffer (output).
       int bytesRead = dataLine.read( buffer, 0, buffer.length );
      final int audioLevel = findAudioLevel(buffer);
      progressBar.setValue(audioLevel);
      System.out.println("Calculated audio level: " + audioLevel);
       if ( bytesRead >= 0 ){
        outputStream.write( buffer, 0, bytesRead );
public int findAudioLevel(byte theAudioData[])
     int level = 1;
     //find audiolevel
     return level;
// Fields
protected TargetDataLine dataLine;
protected ByteArrayOutputStream outputStream;
protected boolean running;
protected byte [] buffer;
static int WAV_HEADER_SIZE = 44;
protected JProgressBar progressBar;
}