Java Reference
In-Depth Information
Summary
In this chapter we have looked at the basic characteristics of Java, and how portability between different
computers is achieved. We have also introduced the elements of object-oriented programming. There
are bound to be some aspects of what we have discussed that you don't feel are completely clear to you.
Don't worry about it. Everything we have discussed here we will be revisiting again in more detail later
on in the topic.
The essential points we have covered in this chapter are:
Java applets are programs that are designed to be embedded in an HTML document. Java
applications are standalone programs. Java applications can be console programs that only
support text output to the screen, or they can be windowed applications with a GUI.
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Java programs are intrinsically object-oriented.
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Java sourcecode is stored in files with the extension
.java
.
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Java programs are compiled to byte codes, which are instructions for the Java Virtual
Machine. The Java Virtual Machine is the same on all the computers on which it is
implemented, thus ensuring the portability of Java programs.
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Java object code is stored in files with the extension
.class
.
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Java programs are executed by the Java interpreter, which analyses the byte codes and carries
out the operations they specify.
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The Java System Development Kit ( the SDK) supports the compilation and execution of Java
applications and applets.
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Experience is what you get when you are expecting something else.
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Resources
You can download the sourcecode for the examples in the topic from any of:
http://www.wrox.com
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ftp://www.wrox.com
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ftp://www.wrox.co.uk
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The sourcecode download also includes ancillary files, such as
.gif
files containing icons for instance,
where they are used in the examples.
If you have any questions on the fine formal detail of Java, the reference works we've used are:
The Java Language Specification
,
Second Edition (The Java Series)
James Gosling et al., Addison-
Wesley,
ISBN 0-201-31008-2
❑
The Java Virtual Machine Specification Second Edition
Tim Lindholm and Frank Yellin, Addison-
Wesley, ISBN 0-201-43294-3,
❑
