Java Development Kit

The Java Development Kit comes with a collection of tools that are used for developing and running Java programs. They include:


• appletviewer ( for viewing Java applet)

• javac (Java compiler)

• java (Java Interpreter)

• javap (Java disassembler)

• javah (for C header files)

• javadoc (for creating HTML documents)

• jdb (Java debugger)

The below figure depicts a Java program, such as an application or applet, that's running on the Java platform. As the figure shows, the Java API and Virtual Machine insulates the Java program from hardware dependencies.

The Java Platform

A platform is the hardware or software environment in which a program runs. The Java

platform differs from most other platforms in that it's a software-only platform that runs on
top of other, hardware-based platforms. Most other platforms are described as a combination of hardware and operating system.
The Java platform has two components:

 • The Java Virtual Machine (Java VM)
• The Java Application Programming Interface (Java API)

The Java VM is the base for the Java platform and is ported onto various hardware-based platforms.
The Java API is a large collection of ready-made software components that provide many useful capabilities, such as graphical user interface (GUI) widgets. The Java API (application programming interface) is grouped into libraries (packages) of related components.