Key Released event is not working Java Swing

Question

I have implemented a event to one of my panels, but is not working at all and i don´t know why.

Here you can see how i implemented the events:

loginPanel = new javax.swing.JPanel();
loginPanel.addKeyListener(new java.awt.event.KeyAdapter() {
            public void keyReleased(java.awt.event.KeyEvent evt) {
                loginPanelKeyReleased(evt);
            }
        });
loginPanel.setLayout(new java.awt.GridBagLayout());
...

private void loginPanelKeyReleased(java.awt.event.KeyEvent evt) {                                       
        System.out.println(evt.getKeyChar());
    } 

Maybe something is missing, but I don't know what it is.

Anyone can help me with this? Thank you!