Java Reference
In-Depth Information
If you're using a Microsoft Windows or Apple Mac OS system, you probably have a
Java interpreter installed that can run Java programs.
To develop Java programs, you need more than an interpreter. You also need a compiler
and other tools that are used to create, run, and test programs.
The Java Development Kit includes a compiler, interpreter, debugger, file archiving pro-
gram, and several other programs.
The kit is simpler than other development tools. It does not offer a graphical user inter-
face, text editor, or other features that many programmers rely on.
To use the kit, you type commands at a text prompt. MS-DOS, Linux, and UNIX users
will be familiar with this prompt, which is also called a command line.
Here's an example of a command you might type while using the Java Development Kit:
javac RetrieveMail.java
This command tells the
javac
program—the Java compiler included with the kit—to
read a source code file called
RetrieveMail.java
and create one or more class files.
These files contain compiled bytecode that can be executed by a Java interpreter.
When
RetrieveMail.java
is compiled, one of the files will be named
RetrieveMail.class
. If the class file was set up to function as an application, a Java
interpreter can run it.
People who are comfortable with command-line environments will be at home using the
Java Development Kit. Everyone else must become accustomed to the lack of a graphical
point-and-click environment as they develop programs.
If you have another Java development tool and you're certain it is completely compatible
with Java 6, you don't need to use the Java Development Kit. Many different develop-
ment tools can be used to create the tutorial programs in this topic.
CAUTION
If you have any doubts regarding compatibility, or this topic is your
first experience with the Java language, you should probably use
JDK 6.
Another free alternative is NetBeans, which can be downloaded
from Sun as a bundle with the kit and offers a graphical user
interface for programming that functions on top of the kit.
