private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        _username = usernameField.getText();
        _password = new String(passwordField.getPassword());
        if (!_username.isEmpty() && !_password.isEmpty()) {
        	clickedOKButton = true;
            setVisible(false);
            try {
            	verifyUser(_username, _password);
            } catch(Exception e){
            	this.showDialog();
            }
        } else {
            JOptionPane.showMessageDialog(this, "Please fill in all the required fields!");
        }
        Test.mutex.release();
    }