jar-java-13 man page

jar — create an archive for classes and resources, and manipulate or restore individual classes or resources from an archive

Synopsis

jar [OPTION ...] [ [--release VERSION] [-C dir] files] ...

Description

The jar command is a general-purpose archiving and compression tool, based on the ZIP and ZLIB compression formats. Initially, the jar command was designed to package Java applets (not supported since JDK 11) or applications; however, beginning with JDK 9, users can use the jar command to create modular JARs. For transportation and deployment, it's usually more convenient to package modules as modular JARs.

The syntax for the jar command resembles the syntax for the tar command. It has several main operation modes, defined by one of the mandatory operation arguments. Other arguments are either options that modify the behavior of the operation or are required to perform the operation.

When modules or the components of an application (files, images and sounds) are combined into a single archive, they can be downloaded by a Java agent (such as a browser) in a single HTTP transaction, rather than requiring a new connection for each piece. This dramatically improves download times. The jar command also compresses files, which further improves download time. The jar command also enables individual entries in a file to be signed so that their origin can be authenticated. A JAR file can be used as a class path entry, whether or not it's compressed.

An archive becomes a modular JAR when you include a module descriptor, module-info.class, in the root of the given directories or in the root of the .jar archive. The following operations described in Operation Modifiers Valid Only in Create and Update Modes are valid only when creating or updating a modular jar or updating an existing non-modular jar:

Note:

All mandatory or optional arguments for long options are also mandatory or optional for any corresponding short options.

Main Operation Modes

When using the jar command, you must specify the operation for it to perform. You specify the operation mode for the jar command by including the appropriate operation arguments described in this section. You can mix an operation argument with other one-letter options. Generally the operation argument is the first argument specified on the command line.

-c or --create

Creates the archive.

-i=FILE or --generate-index=FILE

Generates index information for the specified JAR file.

-t or --list

Lists the table of contents for the archive.

-u or --update

Updates an existing JAR file.

-x or --extract

Extracts the named (or all) files from the archive.

-d or --describe-module

Prints the module descriptor or automatic module name.

Operation Modifiers Valid in Any Mode

You can use the following options to customize the actions of any operation mode included in the jar command.

-C DIR

Changes the specified directory and includes the files specified at the end of the command line.

jar [OPTION ...] [ [--release VERSION] [-C dir] files]

-f=FILE or --file=FILE

Specifies the archive file name.

--release VERSION

Creates a multirelease JAR file. Places all files specified after the option into a versioned directory of the JAR file named META-INF/versions/VERSION/, where VERSION must be must be a positive integer whose value is 9 or greater.

At run time, where more than one version of a class exists in the JAR, the JDK will use the first one it finds, searching initially in the directory tree whose VERSION number matches the JDK's major version number. It will then look in directories with successively lower VERSION numbers, and finally look in the root of the JAR.

-v or --verbose

Sends or prints verbose output to standard output.

Operation Modifiers Valid Only in Create and Update Modes

You can use the following options to customize the actions of the create and the update main operation modes:

-e=CLASSNAME or --main-class=CLASSNAME

Specifies the application entry point for standalone applications bundled into a modular or executable modular JAR file.

-m=FILE or --manifest=FILE

Includes the manifest information from the given manifest file.

-M or --no-manifest

Doesn't create a manifest file for the entries.

--module-version=VERSION

Specifies the module version, when creating or updating a modular JAR file, or updating a non-modular JAR file.

--hash-modules=PATTERN

Computes and records the hashes of modules matched by the given pattern and that depend upon directly or indirectly on a modular JAR file being created or a non-modular JAR file being updated.

-p or --module-path

Specifies the location of module dependence for generating the hash.

@file

Reads jar options and file names from a text file.

Operation Modifiers Valid Only in Create, Update, and

GENERATE-INDEX MODES

You can use the following options to customize the actions of the create (-c or --create) the update (-u or --update ) and the generate-index (-i or --generate-index=FILE) main operation modes:

-0 or --no-compress

Stores without using ZIP compression.

Other Options

The following options are recognized by the jar command and not used with operation modes:

-h or --help[:compat]

Displays the command-line help for the jar command or optionally the compatibility help.

--help-extra

Displays help on extra options.

--version

Prints the program version.

Examples of Jar Command Syntax

Info

2018 JDK 13 JDK Commands