About Java SDK

The Java Development Kit (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 archiver (jar), a documentation generator (javadoc) and other tools needed in Java development.

Java developers are initially presented with two JDK tools, java and javac. Both are run from the command prompt. Java source files are simple text files saved with an extension of .java. After writing and saving Java source code, the javac compiler is invoked to create .class files. Once the .class files are created, the 'java' command can be used to run the java program.

For developers who wish to work in an integrated development environment (IDE), a JDK bundled with Netbeans can be downloaded from the Oracle website. Such IDEs speed up the development process by introducing point-and-click and drag-and-drop features for creating an application.

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.

JDK contents

The JDK has as its primary components a collection of programming tools, including:

• java – the loader for Java applications. This tool is an interpreter and can interpret the class files generated by the javac compiler. Now a single launcher is used for both development and deployment. The old deployment launcher, jre, no longer comes with Sun JDK.
• javac – the compiler, which converts source code intoJava bytecode
• jar – the archiver, which packages related class librariesinto a single JAR file. This tool also helps manage JAR files.
• javadoc – the documentation generator, which automatically generates documentation from source code comments
• jdb – the debugger
• jps – the process status tool, which displays process information for current Java processes
• 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
• extcheck – a utility which can detect JAR-file conflicts
• apt – the annotation-processing 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