Add two telephone handsets to the GUI version of the voice mail program. When you test your program, add a message through one of the handsets and retrieve it through the other

Improve the program of Exercise 8.6 so that the program does not terminate as soon as one of the handset frames is closed. Hint: Don't use a default close operation but install a WindowListener into the frames. The windowClosing method of the listener should call System.exit(0) when the last frame is being closed.

Attachment:- Mailsystem.zip