A JAR (Java ARchive) is a package file format that bundles multiple Java class files, metadata, and resources (like images, sounds, properties files) into a single compressed file, typically using the ZIP algorithm.

# List contents (table of contents) jar tf MyApplication.jar

With a properly configured MANIFEST.MF file, an archive becomes a "runnable JAR," allowing users to launch complex applications with a simple double-click or a single command: java -jar application.jar .

A JAR file has a strict internal structure. If you open a .jar file using a tool like WinZip or unzip , you will typically see:

Java Archive -

# List contents (table of contents) jar tf MyApplication.jar java archive

A JAR file has a strict internal structure. If you open a .jar file using a tool like WinZip or unzip , you will typically see: and resources (like images