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Java is both a popular object-oriented programming language and runtime environment which allows Java programs to run unchanged on most hardware and software platforms.

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Initial help

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Java is a high-level, platform-independent, object-oriented programming language originally developed by Sun Microsystems and released in 1995. Java is currently owned by Oracle, which purchased Sun on April 20, 2009.

Very few computers can run Java programs directly. Therefore the Java environment is normally made available by installing a suitable software component. For Windows computers, this is usually done by downloading the free Java Runtime Environment (JRE) from Oracle which allows the system to run Java programs. The easiest way to do this is from

Developers frequently need additional tools which are available in the free Java Development Kit (JDK) alternative to the JRE, which for Windows must be downloaded from Oracle and installed manually.

Note: Other vendors exist but usually have license fees. For Linux and other platforms consult the operating system documentation.

More information:

Java source code is compiled to an intermediate form (bytecode instructions for the Java Virtual Machine) that can be executed with the java command.

Beginners' resources

  • The Java Tutorials - Starts from scratch on Windows/Linux/Mac and covers most of the standard library.

Day to day resources

Advanced resources

Code Language (used for syntax highlighting): lang-java