JAR

JAR files can be created and extracted using the "jar" command that comes with the JDK. It can be done using zip tools, but as WinZip has a habit of renaming all-uppercase directories and files in lower case, this can raise support calls with whoever shaped the JAR or the tool authors themselves. WinRAR, on the other hand, retains the original case of filenames.

A JAR file has a manifest file located in the path META-INF/MANIFEST.MF. The entries in the manifest file determine how the JAR file will be used. JAR files which are intended to be executed as standalone programs will have one of their classes specified as the "main" class.