The JAVA Sourcebook

Java is an object-oriented programming language, similar to C++, used for programming web applications. If you want to know what it involves, to decide whether it is something in which you might want to develop skills, to gain understanding of concepts such as 'object orientation' and 'concurrent threads', this is a good starting point. If you then want to go on and actually learn Java, the text provides thorough coverage.

The book is in four parts. Part 1 explains how to obtain and install the Java Development Kit and the HotJava (Sun) browser or Java-compatible Netscape. Part 2 covers the Java language (data structures, objects, and classes). Part 3 covers the building of applets and running them. Part 4 summarises the materials in the development kit, including object libraries for handling input and output.



An applet is a small Java program that is loaded into your browser (you need a Java compatible browser) on instruction from the web page you are viewing. The applet then runs in a display area on the page rather like an inline image, except that Java permits animation and interaction as well as static display.

Creating Java applets is not trivial. An applet that displays an analogue clock face showing the system time, or an applet that displays sub-titles for a video clip takes over 100 lines of hefty code. I doubt many of us would want to get involved in this. It seems more likely that in the future we will use items from libraries of ready made applets. In fact something like this already happens in principle when we include check boxes and radio buttons in our HTML forms.

It is also important to distinguish between Java applets and JavaScript. They are different. JavaScript is simpler and consists of program statements included directly in an HTML document and interpreted by the browser. On the other hand Java applets are first written in text using the Java programming language and then compiled into a separate runnable form that is referenced from the source document within applet tags. The Java Sourcebook is about the Java language. It will not help you at all with JavaScript. However, the material is well explained and very readable. This is definitely not one of those hurried and rather superficial texts about the World Wide Web. For once the cover text is accurate, "A Complete Guide to Creating Java Applets for the Web".