I have an internal frame that opens inside a main window. When a button is clicked on the internal frame, I setVisible(false) and open a new internal Frame. Then when I close the second one I setVisible(true) on the first one. Then if I do it again, without restarting the program I get an Array index out of bounds error on my dos window, but the program does not terminiate, and I can continue on. Does anyone know why this happens or is there some error catching or code cleaning I need to do to keep the Array from going out of bounds??