The ideas in this article, originally written to address deficiencies in Java 1.0, have been largely obsoleted by newer releases of Java.

A callback is a mechanism by which the user's action on a software application's graphical user interface (GUI) is connected to the code implementing the application's response to this action. It is a familiar concept to X Toolkit and Motif programmers.

Figure 1: How Callback Works

 The article, published in Volume 3 Issue 4 (April 1998) of the Java Developer's Journal, describes how such a mechanism can be implemented to extend Java's AWT.