File type: Java Archive
What is a .JAR File
These are java archive files that contain all the necessary files for the running of a java application. The JAR files are used for packaging, deploying as well as distributing java applications easily.
It is essentially a compressed file format which uses the ZIP compression algorithm to compress the files together into a single archive file. JAR files have a prescribed directory structure and come with certain specific files that helps identify the JAR file.
These also contain certain configuration information which help the Java Virtual Machine to run the jar as an application. These JAR files can be digitally signed as well. For running these files it is required that the Java Runtime Environment should be installed on the computer.
JAR files are also often used for packaging and distributing java libraries which can then be referenced by java applications and taken advantage of for use in themselves.
It helps modularizing the java applications and separating or segregating the various parts of the application which are not dependent on each other but help the applications separate needs. JAR are also used by the Mozilla Firefox, SeaMonkey, Thunderbird as well as the Sunbird application to store information such as themes and add-ons.