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.