jar

Java Archive tool

TLDR

Create JAR file

$ jar cf [output.jar] [files...]

Create with manifest

$ jar cfm [output.jar] [MANIFEST.MF] [files...]

Extract JAR file

$ jar xf [archive.jar]

List contents

$ jar tf [archive.jar]

Create executable JAR

$ jar cfe [output.jar] [MainClass] [files...]

Update JAR file

$ jar uf [archive.jar] [newfiles...]

Extract specific file

$ jar xf [archive.jar] [path/to/file]

List contents verbosely

$ jar tvf [archive.jar]

Create JAR from directory using -C to change base dir

$ jar cf [output.jar] -C [build/classes] .

SYNOPSIS

jar [options] [manifest] destination input-files

jar is the Java Archive tool. It packages Java class files, resources, and metadata into a single JAR file for distribution and deployment.JAR files use ZIP format with a manifest (META-INF/MANIFEST.MF) containing metadata. Executable JARs specify a main class in the manifest.

PARAMETERS

Create new archive.

Extract archive.

List table of contents.

Update existing archive.

f file

Specify archive filename.

m manifest

Include manifest file.

e class

Set entry point (main class).

Verbose output.

Store only (no compression).

Do not create a manifest file.

Generate index information for specified JAR files.

C dir

Change to directory before including the following files.

--release VERSION

(Java 9+) Place following files in a versioned directory for multi-release JARs.

MANIFEST EXAMPLE

$ Manifest-Version: 1.0
Main-Class: com.example.Main
Class-Path: lib/dependency.jar

CAVEATS

Order of flags matters when using legacy (non-dashed) syntax. The manifest file must end with a newline. Paths are relative to the current directory unless -C is used. In Java 9+ the `--module-version` and `--release` flags add module/multi-release support.

HISTORY

The jar tool has been part of the JDK since Java 1.1 (1997). It's essential for Java deployment, evolving to support modules in Java 9+ and multi-release JARs.

jar