Program: 45711
Project: 45711
Buggy source:
/** 
 * Attempt to use the current avatar. Close the window if so.
 */
private void use(){
  final AvatarRegistry registry=AvatarRegistry.getAvatarRegistry();
  final String newAvatarName=nameTextField.getText().trim();
  if (newAvatarName == null || newAvatarName.equals("String_Node_Str") == true) {
    String msg="String_Node_Str";
    JOptionPane.showMessageDialog(this,msg,"String_Node_Str",JOptionPane.ERROR_MESSAGE);
    return;
  }
  if (newAvatarName.indexOf("String_Node_Str") != -1) {
    String msg="String_Node_Str";
    JOptionPane.showMessageDialog(this,msg,"String_Node_Str",JOptionPane.ERROR_MESSAGE);
    return;
  }
  AvatarSPI oldAvatar=registry.getAvatarByName(newAvatarName);
  if (newAvatarName.equals(originalAvatarName) == false && oldAvatar != null) {
    String msg="String_Node_Str" + newAvatarName + "String_Node_Str"+ "String_Node_Str";
    JOptionPane.showMessageDialog(this,msg,"String_Node_Str",JOptionPane.ERROR_MESSAGE);
    return;
  }
  if (newAvatarName.equals(originalAvatarName) == true) {
    setBusy(true);
    new Thread(){
      @Override public void run(){
        avatar.setAvatarParams(currentParams);
        save(avatar);
        registry.setAvatarInUse(avatar,false);
        SwingUtilities.invokeLater(new Runnable(){
          public void run(){
            setBusy(false);
            setVisible(false);
          }
        }
);
      }
    }
.start();
    return;
  }
  setBusy(true);
  new Thread(){
    @Override public void run(){
      ImiAvatar newAvatar=ImiAvatar.createAvatar(newAvatarName);
      newAvatar.setAvatarParams(currentParams);
      save(newAvatar);
      registry.setAvatarInUse(newAvatar,false);
      if (registry.getAvatarByName(originalAvatarName) != null) {
        avatar.delete();
      }
      SwingUtilities.invokeLater(new Runnable(){
        public void run(){
          setBusy(false);
          setVisible(false);
        }
      }
);
    }
  }
.start();
}

Fixed version (ground truth):
/** 
 * Attempt to use the current avatar. Close the window if so.
 */
private void use(){
  final AvatarRegistry registry=AvatarRegistry.getAvatarRegistry();
  final String newAvatarName=nameTextField.getText().trim();
  if (newAvatarName == null || newAvatarName.equals("String_Node_Str") == true) {
    String msg=BUNDLE.getString("String_Node_Str");
    String title=BUNDLE.getString("String_Node_Str");
    JOptionPane.showMessageDialog(this,msg,title,JOptionPane.ERROR_MESSAGE);
    return;
  }
  if (newAvatarName.indexOf("String_Node_Str") != -1) {
    String msg=BUNDLE.getString("String_Node_Str");
    String title=BUNDLE.getString("String_Node_Str");
    JOptionPane.showMessageDialog(this,msg,title,JOptionPane.ERROR_MESSAGE);
    return;
  }
  AvatarSPI oldAvatar=registry.getAvatarByName(newAvatarName);
  if (newAvatarName.equals(originalAvatarName) == false && oldAvatar != null) {
    String msg=BUNDLE.getString("String_Node_Str");
    msg=MessageFormat.format(msg,newAvatarName);
    String title=BUNDLE.getString("String_Node_Str");
    JOptionPane.showMessageDialog(this,msg,title,JOptionPane.ERROR_MESSAGE);
    return;
  }
  if (newAvatarName.equals(originalAvatarName) == true) {
    setBusy(true);
    new Thread(){
      @Override public void run(){
        avatar.setAvatarParams(currentParams);
        save(avatar);
        registry.setAvatarInUse(avatar,false);
        SwingUtilities.invokeLater(new Runnable(){
          public void run(){
            setBusy(false);
            setVisible(false);
          }
        }
);
      }
    }
.start();
    return;
  }
  setBusy(true);
  new Thread(){
    @Override public void run(){
      ImiAvatar newAvatar=ImiAvatar.createAvatar(newAvatarName);
      newAvatar.setAvatarParams(currentParams);
      save(newAvatar);
      registry.setAvatarInUse(newAvatar,false);
      if (registry.getAvatarByName(originalAvatarName) != null) {
        avatar.delete();
      }
      SwingUtilities.invokeLater(new Runnable(){
        public void run(){
          setBusy(false);
          setVisible(false);
        }
      }
);
    }
  }
.start();
}