Overview
JAR files are Java's way of distributing libraries and executable programs. JAR is short for Java ARchive. JARs are just ZIP files with a .jar extension and a special directory structure. They can contain the programs or library's classes as well as any other files they may need. A special file called /META-INF/MANIFEST.MF is often required to be in the archive and contains information about the JAR content, such as the name of the main class and its dependencies.
When to use JARs
Use JARs when..
- you want to bundle a Java application's files for distribution, or
- you need to deploy your code at a place where you need it as a JAR, or
- you need to sign your code, for example to execute it in a web browser or on a cell phone
Java supports JARs since version 1.1 (in other words, practically forever).
