Experience programming applets with Ada95

Abstract

Because of its ability to provide platform independent programs and active content on web pages, Java has created much excitement in the computer science community. However, much of the computer science community does not have a good understanding of the Java technology. Java is much more than simply a language for developing programs which run on web pages. It is an environment for developing programs which take advantage of the Internet, and the use of the Java language is only one piece of that environment. That other languages can be used to write programs which can take advantage of the Java environment is shown by the existence of two such languages, NetRexx [1] from IBM and AppletMagic(tm) [2], an implementation of Ada95 for the Java VM, from Intermetrics.George Washington University obtained a Beta copy of the AppletMagic(tm) compiler in January of 1996. Since that time, we have been attempting to include AppletMagic and Java in a Data Structures (CS2) course and a course on Design of User Interface Software. During this time we have developed some experience in using Ada95 to develop Java programs and applets, and some insights into how students use the Java environment. This paper will report on those experiences.We will first present an overview of the Java environment. Intended to provide readers who are unfamiliar with Java enough background to be able to understand the relationship of AppletMagic(tm) and the Java environment. The third section will cover the structure of applets, and how to create an applet in Ada. The fourth section will cover issues concerning using classes written in Java from Ada, and some of the experiences we have had in using Ada to develop Java programs and applets, Finally the fifth section will present conclusions we have drawn from using AppletMagic(tm) in our courses.