Understanding the directory structure of JDK (Java SDK)

In this tutorial ,We will discuss about the directory structure of jdk

Understanding the directory structure of  JDK (Java SDK)

Generally jre is installed with jdk so here we are discussing about the both of jdk and jre,directory and file structure. The file structure of jre is identical to that of the JDK's jre directory.

General files and Directories

		\jdk1.6.0
        ___________|____________________
       |           |                    |
      \bin	  \lib		       \jre
       |           |          __________|_____________________
   java.exe    tools.jar     |                                |        
   javac.exe   dt.jar       \bin                              \lib                
   javap.exe            _____|____ __________             ______|_______ ________ ________        
   javah.exe           |          |          |           |	    |       |        |        |
   javadoc.exe     java.exe    \client     \server      rt.jar	      \ext  \security  \applet   \fonts
                   java.dll       |          |      charsets.jar        |                  
                   awt.dll     jvm.dll    jvm.dll                   localedata.jar            

Now the explanation of the above structure is as follows:-

Let's suppose the JDK software is installed at D:\jdk1.6.0

D:\jdk1.6.0:-It is the root directory of JDK installation. It contains the Copyright, license, README files, src.zip,and the archive of source code for the Java platform.

D:\jdk1.6.0\bin:-Bin contains the executable (.exe) files for the development tools. This directory should contain by the PATH Environment Variables.

D:\jdk1.6.0\lib:-The development tools used these files. In this'toos.jar', which contains non-core classes for support of the tools and utilities in the jdk and 'dt.jar'(DesignTime archive of Bean Info) files which tell interactive development environments(IDE'S) how to display java components and how to let the developer customize them for an application, are included.

D:\jdk1.6.0\jre:-It is the root directory of the Java Runtime Environment. it is used by the JDK development tools. The JRE helps to run applets and applications written in the Java programming language by providing the libraries, JVM, and other components.

D:\jdk1.6.0\jre\bin:-It contains the Executable files and DLLs for the tools and Java platform. The executable files available in \jdk1.6.0\jre\bin are identical to the file available in \jdk1.6.0\bin. There is no need to be a path of this directory in Environment Variables.

D:\jdk1.6.0\jre\bin\client:-This directory contains the DLLs files which are used by Java HotSpot Client Virtual Machine.

D:\jdk1.6.0\jre\bin\server:- This directory contains the DLLs files which are used by Java HotSpot Server Virtual Machines.

D:\jdk1.6.0\jre\lib:-It contains the Code libraries, property settings, and resource files which are used by the Java runtime environment.
For example:-
  1. rt.jar:-The bootstrap classes (these are the Runtime classes that comprise the Java platform's core API).
  2. charsets.jar:- These are Character conversion classes.

D:\jdk1.6.0\jre\lib\ext:-It contains extensions of default installation directory for the Java platform.
for example:-
localedata.jar:-locale data for java. text and java.util.

D:\jdk1.6.0\jre\lib\security:-It contains the files which are used for security management. These includes the security policy (java.policy) and security properties (java. security) files.

D:\jdk1.6.0\jre\lib\applet:-Applets can be placed in this directory by the supporting classes which are contained by jar files.

D:\jdk1.6.0\jre\lib\font:-It contains the font files (TrueType) used by the Java platform.

Additional files and Directories
These are the directory contains demos, java source code, and C header files

					\jdk1.6.0
				 ___________|____________________
				|           |                    |
   			  \demo	    \include		     \src.zip
		 ___________|___________ ___________
		|           |           |           |
	   \applets       \jfc      \jpda      \plugin

D:\jdk1.6.0\demo:-This directory contains the Examples with Source code that shows how to program for the Java platform.
D:\jdk1.6.0\include:- It contains the 'C' language header files and it uses the Java Native Interface and the Java Virtual Machine Debugger Interface to support native-code programming.
D:\jdk1.6.0\src.zip:- It contains the source code for the Java platform.
D:\jdk1.6.0\applets:- It contains the applets that can be used on a web page.
D:\jdk1.6.0\jfc:- Contains Examples of Java 2D and JFC\SWING functionality.
D:\jdk1.6.0\jpda:- Contains Examples of Java Platform Debugging Architecture and includes source code for the javadt and jdb utilities.
D:\jdk1.6.0\plugin:-It contains the demos for how to use with the java plug-in product.