The GridBagLayout constructor is trivial,
GridBagLayout() with no arguments. You use it like this:
GridBagLayout gbl = new GridBagLayout();
Unlike the GridLayout() constructor, this constructor does not
specify the number of rows or columns. This is determined by
the cells your program refers to. If you put a component in row 8
and column 2, then Java will make sure there are at least nine rows
and three columns. (Rows and columns start counting at zero.) If
you later put a component in row 10 and column 4, Java will add the
necessary extra rows and columns. You may have a picture in your
mind of the finished grid, but Java does not need to know this when
you create a GridBagLayout.
Unlike with most other layout managers, you should not create a
GridBagLayout inside a call to setLayout(). You
will need access to the GridBagLayout object later in
the applet when you add components to the container.