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Java is a programming language created by SUN and released for the first time in 1998.
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Java is a programming language created by [www.sun.com SUN] and released for the first time in 1998.
Main characteristics
The main characteristic of Java are:
- it enhances strict Object Oriented programming model
- it provides a bundled almost complete set of APIs that release the programmer from having to deal with trivial problems to focus on the core logic of their software.
- It's run by a Virtual Machine, this means that it's compiled into a special format that is understood by the virtual machine.
- The Virtual Machine is available on many different platforms, so the software developed in Java can be executed on any computer that loads a Virtual Machine.
Editions of Java
Java comes in three different packages:
- Java Standard Edition (Java SE)
- Which contains all the core functionalities of the language, allows to produce standalone software to be run on desktop computers as well as on servers, on embedded and realt time environments.
- Java Enterprise Edition (Java EE)
- Is a set of libraries and extensions to the Java Standard Edition specifically created for helping the production of enterprise software.
- Java Micro Edition (Java ME)
- Is a reduced set of the Java SE made for running on Mobile or embedded devices.
JDK vs. JRE
Java is distributed in two main packages:
- The Java Runtime Environment (JRE)
Is the package containing only what's necessary to run programs made in Java. The JRE contains a Virtual Machine that allows you to run any Java program. This is what you normally need if you are not a programmer and simply want to run Java software.
- The Java Development Kit (JDK)
- Is the package containing all the programs and utilities necessary to compile your Java source code. This package is what you need if you are a programmer and want to write software in Java. The JDK contains in addition a JRE, that is used for executing the software you compile with the JDK. If you install the JDK you normally won't need to install the JRE too.
The Java Virtual Machine
The Java Virtual Machine (JVM) is simply a program that you can run on your computer.
This program is able to read the special format Java Programs are compiled to and execute the commands specified in them.
Quick start in Java
If you are or want to be a programmer the best thing to do for starting is to install the JDK for Java SE. Installing the JDK contains a tutorial for doing so.
If you want to be simply an user for Java Software read and follow the tutorial: Installing the JRE.
See Also
http://java.sun.com/, Installing the JDK, Installing the JRE
Comments from the users
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"Small bananas are not bananas for real. Only look similar and taste the same."
interesting point
Small bananas are just bananas smaller. Let's talk about java, now
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Java is one of programming LANGUAGES, object oriented (like C++,Perl,Javascript,Python etc.).
Java was invented by SUN Microsystems and JDK relased by SUN brings good quality "compiler" and JVM (you can consider JVM as a virtual computer - if you call javac program "compiler").
Interesting thing about Java code is that it is interpreted language for real (at least i havent heard about proper java language straight compilers (maybe because there is no sense acctually to make one, whats for?) ). "Compiler" doesnt produce a real executables, but BYTECODE, that bytecode is the exact INTERPRETED code by JVM, you can compare it to PERL or ECMA Script (Javascript) the difference makes CLASS LOADER, thats the moment when small makes big difference.
--86.163.174.232 15:17, 27 November 2008 (UTC)