The short answer: Java is both a programming language and the software platform that runs programs written in it. The platform comes as a JDK, to build programs, or a runtime, to run them, from Oracle and from other vendors. Which one you install decides whether you owe Oracle a licence. See Java license changes, year by year.
What is Java?
Java is a technology consisting of:
- a programming language and
- a software platform.
Java is an object-oriented programming language and software platform that runs on billions of devices, including notebook computers, mobile devices, gaming consoles, medical devices and many others.
The rules and syntax of Java are based on the C and C++ languages.
Why Java is popular
The core philosophy behind its creation, interoperability across disparate devices, remains the strongest argument for favoring Java for new enterprise applications. Platform scalability is a key attribute of Java. With Java, you can use one single system across a broad range of use cases. Existing desktop applications can be easily adapted to run on smaller devices that have limited resources.
Java’s object-oriented architecture allows you to
- create modular programs and reusable code,
- shortens development cycles and
- extends the longevity of enterprise applications.
JDK, JRE and JVM
JVM: Java Virtual Machine
The JVM is an abstract machine that enables your computer to run a Java program. The JVM makes Java a ‘platform-independent language’. When you write Java code, it is written to be executed in the JVM and not the specific computer (physical machine).
JDK: Java Development Kit
It is a bundle of software that is used to develop Java programs. Contains the Java compiler, the JRE, API Classes & additional files to write Java programs. Different versions available are: Oracle JDK, OpenJDK, AzulJDK etc.
JRE: Java Runtime Environment
This is an implementation of the Java Virtual Machine & containing additional components and core libraries to run applications and applets written in Java
Java SE: Java Standard Edition
This is the Oracle supported Java platform. Interchangeably used with Oracle JDK
Diagram view of Java components
JAVA ULA
An audit letter, a renewal quote or a ULA end date on your desk? We check what Oracle, Microsoft, IBM or Broadcom is claiming, work out what you owe under your contract, defend against audits, and negotiate the rest down.