http://www.daniweb.com/techtalkforums/post58331.html
To implement an interface (in this case ActionListener or ItemListener), you must write all the functions that the interface provides. One such function you're missing is actionPerformed(ActionEvent). If you put this function into your ChatClientApplication class, it will stop complaining.
Put this in your class:
Code:
public void actionPerformed(java.awt.event.ActionEvent e)
{
}
Hope this helps!
Ed