◀ Prev · Parts · Full · Next ▶

The platform uses the

Java

programming language and is part of the Java software-platform family. Java SE defines a range of general-purpose

APIs

—such as

Java APIs

for the

Java Class Library

—and also includes the

Java Language Specification

and the

Java Virtual Machine Specification

.

OpenJDK

is the official

reference implementation

since version 7.

Jakarta EE

, formerly Java Platform, Enterprise Edition (Java EE) and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending

Java SE

with specifications for enterprise features such as

distributed computing

and

web services

.

Jakarta EE applications are run on

reference runtimes

, which can be

microservices

or

application servers

, which handle transactions, security, scalability,

concurrency

and management of the components they are deploying.

The heart of the Java platform is the "virtual machine" that executes Java bytecode programs. This bytecode is the same no matter what hardware or operating system the program is running under. However, new versions, such as for Java 10 (and earlier), have made small changes, meaning the bytecode is in general only forward compatible. There is a JIT (Just In Time) compiler within the Java Virtual Machine, or JVM. The JIT compiler translates the Java bytecode into native processor instructions at run-time and caches the native code in memory during execution.

◀ Prev · Parts · Full · Next ▶