■ jre: This subdirectory contains the JDK's private copy of the JRE, which lets you run Java programs without having to download and install the public JRE. You will discover some of these tools shortly. ■ bin: This subdirectory contains assorted JDK tools, including the Java compiler tool. The home directory contains various files (such as README.html, which provides information about the JDK, and src.zip, which provides the standard class library source code) and subdirectories, including the following three important subdirectories: That way, you will be able to execute JDK tools from any directory in your filesystem.įinally, you might want to create a projects subdirectory of the JDK's home directory to organize your Java projects, and create a separate subdirectory within projects for each of these projects. TIP: After installing the JDK, you should add the bin subdirectory to your platform's PATH environment variable.
(It can also install the public JRE in another directory.) On my Windows XP platform, the home directory is C:\Program Files\Java\jdk1.6.0_16-JDK 6 Update 16 was current when I began this book. The JDK installer installs the JDK in a home directory. NOTE: Some of this book's code requires JDK 7, which is only available as a preview release ( ) at time of writing. Click the Download JDK link to download the current JDK's installer program for your platform. The Java SE Downloads page also provides access to the current JDK, which is JDK 6 Update 20 at time of writing.
JDK 5 was the first JDK to also provide an internal version number: 1.5.0. For example, JDK 1.0 identifies Java version 1.0, and JDK 5 identifies Java version 5.0. Over the years, numerous JDKs have been released, with JDK 7 set for release in fall or winter 2010.Įach JDK's version number identifies a version of Java. Until JDK 6 arrived, JDK stood for Java Development Kit (SE was not part of the title). NOTE: JDK 1.0 was the first JDK to be released (in May 1995). For that task, you need to download and install the Java SE Development Kit (JDK), which contains development tools (including the Java compiler) and a private JRE. However, the public JRE does not make it possible to develop Java programs. The public JRE can be downloaded from the Java SE Downloads page ().
The Java Runtime Environment (JRE) implements the Java SE platform and makes it possible to run Java programs.