Uniquely, Eclipse extensively employs plug-ins to provide functionalities, which are usually built-in on most of IDEs. By creating plug-inss, Eclipse can support any language such as Java or C, and building tools such as compilers and debuggers. Eclipse and its plug-ins are written in the Java programming language.
The user-interface of Eclipse uses a GUI framework called SWT. Unlike AWT or Swing of Java, SWT uses native widgets such as buttons. It makes Eclipse work faster than Swing, which emulates any widgets by pure Java code.