Eclipse editor can be used for various programming language. Depending on your language you may need to do some setting in your editor. File type can be one such thing. *.class is the common file extension used for many language. If you are a PHP developer then you will like to associate *.class with php editor, so that when you click on *.class in file browser on left side of editor, contents inside *.class file use php color and other default setting of PHP language.
