.setVisible() not working

Java Code:

public void mouseClicked(MouseEvent e) {                                       
        if (textAddedPlayerName.getText().equals("")) {                                               
                lblERROR.setVisible(true);              
                long start = System.currentTimeMillis();
                long current = System.currentTimeMillis();
                while (current - start < 2000) {
                        current = System.currentTimeMillis();
                }                                               
                lblERROR.setVisible(false);     
        }else {
                String temp = textAddedPlayerName.getText();
                list.add(temp); 
        }
        }
});

Whenever I run this code my lblERROR label does not seem to become visible, the timer just starts and runs for the 2 seconds. I read online about repainting but that also did not help.

lblERROR was added onto a panel if that has something to do with it.

Also is their a better way to make a timer, as this while loop causes that no other operations can be done by the user, ex he cant type anything in textAddedPlayerName for the 2 seconds.

PS: I'm just starting to learn Swing , so please be gentle.