GraphicsConfiguration在Java中代表什么？

Question

The Java 8 documentation describes GraphicsConfiguration in the following manner.

The GraphicsConfiguration class describes the characteristics of a graphics destination such as a printer or monitor

The description is a bit non-technical and vague, though, it has been enough to allow me to use it in a screenshot application, but I still do not understand why a GraphicsDevice has multiple GraphicsConfigurations. In the documentation for GraphicsDevice it states:

Each graphics device has one or more GraphicsConfiguration objects associated with it. These objects specify the different configurations in which the GraphicsDevice can be used.

What are these "different configurations" and when would they occur?

Answer 1

As stated in the Javadoc for this class:

There can be many GraphicsConfiguration objects associated with a single graphics device, representing different drawing modes or capabilities. The corresponding native structure will vary from platform to platform. For example, on X11 windowing systems, each visual is a different GraphicsConfiguration. On Microsoft Windows, GraphicsConfigurations represent PixelFormats available in the current resolution and color depth.

http://docs.oracle.com/javase/7/docs/api/java/awt/GraphicsConfiguration.html

For X11 and the term "visual" this link clarifies a bit: http://tronche.com/gui/x/xlib/utilities/visual.html - Of course, for "normal" applications this might be irritating but since Java AWT uses the underlying OS graphics, it has to represent its characteristics.