Example of KeyListener

private void addKeyListeners() {
        this.addKeyListener(
            new KeyListener() {
                @Override
                public void keyTyped(KeyEvent e) {
                    //throw new UnsupportedOperationException("Not supported yet.");
                }

                @Override
                public void keyPressed(KeyEvent e) {

                    inputField.setText(inputField.getText() + String.valueOf(e.getKeyChar()));
                }

                @Override
                public void keyReleased(KeyEvent e) {
                    //throw new UnsupportedOperationException("Not supported yet.");
                }
            }
        );
    }