Java technology is both a programming language and a
platform.
The Java programming language is a high-level,
object-oriented language. Java programs are both compiled and interpreted.
Compilation translates Java code into an intermediate language called Java
bytecode. Bytecode is in turn parsed and run (interpreted) by the Java Virtual
Machine (JVM) — a translator between the language and the underlying operating
system and hardware. A compiled Java program can run on any system that has a
version of the JVM.
The Java platform is a software-only platform that can run on
top of most hardware platforms. It consists of the JVM and the Java API — a
large collection of ready-made components (classes) that ease application
development and deployment. The Java API spans everything from basic objects,
to networking and security, to XML generation and web services. It is grouped
into libraries — known as packages — of related classes and interfaces.