A good answer might be:

A window.

A GUI program consists of a collection of graphical components that are all placed inside one or more windows. You think of most components as being "contained" by a particular window. In GUI programming, a container is an object that has GUI components placed inside of it.

In Java, a frame is a window that has nice borders, various buttons along the top border, and other built in things. What you usually call a "window" Java calls a "frame." A frame is a container object, so GUI components can be placed in it.

Like all software objects, a frame-object is actually a section of main memory that holds information and methods. The Java system, with the help of the operating system and the graphics board, paints a picture on the computer monitor that represents the frame. For convenience, people often speak as if the frame were the actual picture on the monitor. When a "button is placed in a frame" it is easy to visualize this with what you see on the monitor. In fact, what is happening, is the data in the main memory for the frame is being updated.

A minimal Java graphical user interface consists of a single frame.

QUESTION 5:

Will a minimal GUI program have an event listener?