Obtaining the Java Development Kit - Java Sample Program

Obtaining the Java Development Kit

 Now that the theoretical underpinning of Java has been explained, it is time to start writing Java programs. Before you can compile and run those programs, however, you must have the Java Development Kit (JDK) installed on your computer. The JDK is available free of charge from Oracle. At the time of this writing, the current release of the JDK is JDK 7.

 The JDK can be downloaded from www.oracle.com/technetwork/java/javase/downloads/index.html. Just go to the download page and follow the instructions for the type of computer that you have. After you have installed the JDK, you will be able to compile and run programs. The JDK supplies two primary programs. 
The first is javac, which is the Java compiler. The second is java, which is the standard Java interpreter and is also referred to as the application launcher.

One other point: The JDK runs in the command prompt environment and uses command-line tools. It is not a windowed application. It is also not an integrated development environment (IDE).

NOTE:
 In addition to the basic command-line tools supplied with the JDK, there are several high-quality IDEs available for Java, such as NetBeans and Eclipse. An IDE can be very helpful when developing and deploying commercial applications. As a general rule, you can also use an IDE to compile and run the programs in this book if you so choose. However, the instructions presented in this book for compiling and running a Java program describe only the JDK command-line tools. The reasons for this are easy to understand. First, the JDK is readily available to all readers. Second, the instructions for using the JDK will be the same for all readers. Furthermore, for the simple programs presented in this book, using the JDK command-line tools is usually the easiest approach. If you are using an IDE, you will need to follow its instructions. Because of differences between IDEs, no general set of instructions can be given