The Java Development KitAudio
The standard tool for developing Java programs is Suns Java Development Kit or JDK. This is freely downloadable from the Sun website and is updated according to the current version. So for example at the time of writing the current version is JDK1.4. The current version number is often represented as a point release, i.e. JDK126.96.36.199. The JDK is under constant development and each new release brings new features, performance and bug fixes, so it is generally a good idea to download the latest version.
The JDK is a a very "bare bones" tool that expects you to work from the command prompt, i.e. That black box under Windows that runs cmd.exe or possibly command.com.
There are several more friendly development tools with the sort of menus, windows and prompts that you expect from a modern program. These types of tools are sometimes called Integrated Development Environments or IDE, and they can include debuggers and visual design tools that allow programs to be created using "drag and drop". One of the problems with this type of graphical tool is that the interface can "get in the way" of understanding what is happening. To start off with the examples will assume you are using the JDK from the prompt and using a plain text editor such as notepad under windows or vi under Linux/Unix.