AWT Containers serve as holders for other AWT objects. Java has two graphics libraries for historical reasons. The AWT was released with JDK 1.01, and when it was found to be inefficient the Swing library was added. So many applications were written with AWT that it was judged impractical to remove it.
A List object is similar to a Choice object, except that the List allows more than one item to be displayed at the time. It also allows more than one item to be selected at the same time.
The GridBagLayout is the most powerful, but also the most complex of the layout managers.