In previous chapters most of the discussion centered around GNU development tools and programming in C and C++ languages. This chapter is devoted to Java development and describes how to use some Java tools and a Java virtual machine.
As many of the readers already know, Java is a different language compared to other compile-and-execute languages in that it needs a Java virtual machine (JVM) to execute what is called byte code. Each platform has its own implementation of the Java virtual machine. There are many JVMs available on Linux platform in free and open source as well as commercial domains. Some virtual machines are also available for embedded Linux platforms that are very small in size and need little memory to execute. You can select a virtual machine based upon your requirements. Java virtual machines are built on Java Language Specifications (JLS). Information about JLS and books in downloadable format can be found at http://java.sun.com/docs/books/jls/.
This chapter provides some information about how to use different development tools on Linux. The most commonly available tools are Sun SDK and GNU gcj compiler. Kaffe and Jboss are other very popular open source development tools on Linux and these are introduced in this chapter. However please note that this chapter is not a tutorial on Java language and if you are new to the language, you get help from many other resources on the Internet as well as in print media. Some of the most popular include Sun Java SDK, IBM Java SDK, Kaffe, and