› Tech › Eclipse, Editor Eclipse Editor – Associating a file type to editor 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.