What is inside JDK ?

         We have already seen the Three Bigshots of Java - JDK , JRE , JVM .Now we will see what actually does the Java Development Kit (JDK) contains. The Java Development Kit (JDK) is a Sun Microsystems product aimed at Java developers . On 17 November , 2006 , Sun released it under the General Public License , thus making it free software . This happened in large part on 8 May 2007, when Sun contributed the source code to the OpenJDK . 

A Java Development Kit (JDK) is a program development environment for writing Java applets and applications. It consists of a runtime environment that "sits on top" of the hardware - the operating system layer as well as the tools and programming that developers need to compile, debug, and run applets and applications written in the Java language.

For the diagram of JDK :- Click Here

JDK Contents

The JDK has the following primary components as its contents :-

• java – the loader for Java applications. This tool is an interpreter and can interpret the class files generated by the javac compiler.
• javac – the Java compiler, which converts source code into Java bytecode
• jar – (Java ARchive) is an archive file format typically used to aggregate many Java class files and associated metadata and resources (text, images and so on) into one file to distribute application software or libraries on the Java platform.
• javadoc – the documentation generator, which automatically generates documentation from source code comments.
• javap – the class file disassembler.
• appletviewer – this tool can be used to run and debug Java applets without a web browser.
• javah – the C header and stub generator, used to write native methods .
• javaws – the Java Web Start launcher for JNLP applications . 
• jdb – the Java debugger . 
• JConsole – Java Monitoring and Management Console . 
• extcheck – a utility which can detect JAR-file conflicts .
• javafxpackager – tool to package and sign JavaFX applications
• keytool – tool for manipulating the keystore .
• pack200 – JAR compression tool .
• jhat – (experimental) Java heap analysis tool .
• jstack – (experimental) utility which prints Java stack traces of Java threads .
• jstat – (experimental) Java Virtual Machine statistics monitoring tool .

Note :There are many more contents in Java Development Kit (JDK) .

**The Java Development Kit (JDK) also comes with a complete Java Runtime Environment (JRE) , usually called a private runtime .It consists of a Java Virtual Machine and all of the class libraries  present in the production environment , as well as additional libraries only useful to developers , such as the internalization libraries and the Interactive Data Language (IDL) libraries.

**There are different JDKs for various platforms. The supported platforms include Windows , Linux and Solaris. Mac users need a different software development kit , which includes adaptations of some tools found in the JDK.

Note : The JDK forms extended subset of a Software Development Kit (SDK) . Along with JDK , the SDK is composed of extra software , such as Application Servers , Debuggers , and Documentation.

So , we have learnt about the Java Development Kit that JDK is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (java), a compiler (javac), an Java ARchiver (jar), a documentation generator (javadoc) and other tools needed in Java development.


Keep Compiling !!