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jar(1) Basic Tools jar(1)
NAME
jar - Manipulates Java Archive (JAR) files.
SYNOPSIS
Create JAR file
jar c[efmMnv0] [entrypoint] [jarfile] [manifest] [-C dir] file ... [-Joption ...] [@arg-file ...]
Update JAR file
jar u[efmMnv0] [entrypoint] [jarfile] [manifest] [-C dir] file ... [-Joption ...] [@arg-file ...]
Extract JAR file
jar x[vf] [jarfile] file ... [-Joption ...] [@arg-file ...]
List Contents of JAR file
jar t[vf] [jarfile] file ... [-Joption ...] [@arg-file ...]
Add Index to JAR file
jar i jarfile [-Joption ...] [@arg-file ...]
DESCRIPTION
The jar command is a general-purpose archiving and compression tool, based on ZIP and the
ZLIB compression format. However, the jar command was designed mainly to package Java
applets or applications into a single archive. When the components of an applet or
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 allows individual entries in a file to be signed by the applet author so that their
origin can be authenticated. A JAR file can be used as a class path entry, whether or not
it is compressed.
The syntax for the jar command resembles the syntax for the tar command. It has several
operation modes, defined by one of the mandatory operation arguments. Other arguments are
either options that modify the behavior of the operation, or operands required to perform
the operation.
OPERATION ARGUMENTS
When using the jar command, you have to select an operation to be performed by specifying
one of the following operation arguments. You can mix them up with other one-letter
options on the command line, but usually the operation argument is the first argument
specified.
c Create a new JAR archive.
i Generate index information for a JAR archive.
t List the contents of a JAR archive.
u Update a JAR archive.
x Extract files from a JAR archive.
OPTIONS
Use the following options to customize how the JAR file is created, updated, extracted, or
viewed:
e Sets the class specified by the entrypoint operand to be the entry point for a
standalone Java application bundled into an executable JAR file. The use of this
option creates or overrides the Main-Class attribute value in the manifest file.
The e option can be used when creating (c) or updating (u) the JAR file.
For example, the following command creates the Main.jar archive with the Main.class
file where the Main-Class attribute value in the manifest is set to Main:
jar cfe Main.jar Main Main.class
The Java Runtime Environment (JRE) can directly call this application by running
the following command:
java -jar Main.jar
If the entry point class name is in a package, then it could use either the dot (.)
or slash (/) as the delimiter. For example, if Main.class is in a package called
mydir, then the entry point can be specified in one of the following ways:
jar -cfe Main.jar mydir/Main mydir/Main.class
jar -cfe Main.jar mydir.Main mydir/Main.class
Note
Specifying both m and e options together when a particular manifest also contains
the Main-Class attribute results in an ambiguous Main-Class specification. The
ambiguity leads to an error and the jar command creation or update operation is
terminated.
f Sets the file specified by the jarfile operand to be the name of the JAR file that
is created (c), updated (u), extracted (x) from, or viewed (t). Omitting the f
option and the jarfile operand instructs the jar command to accept the JAR file
name from stdin (for x and t) or send the JAR file to stdout (for c and u).
m Includes names and values of attributes from the file specified by the manifest
operand in the manifest file of the jar command (located in the archive at META-
INF/MANIFEST.MF). The jar command adds the attribute's name and value to the JAR
file unless an entry already exists with the same name, in which case the jar
command updates the value of the attribute. The m option can be used when creating
(c) or updating (u) the JAR file.
You can add special-purpose name-value attribute pairs to the manifest that are not
contained in the default manifest file. For example, you can add attributes that
specify vendor information, release information, package sealing, or to make JAR-
bundled applications executable. For examples of using the m option, see Packaging
Programs at http://docs.oracle.com/javase/tutorial/deployment/jar/index.html
M Does not create a manifest file entry (for c and u), or delete a manifest file
entry when one exists (for u). The M option can be used when creating (c) or
updating (u) the JAR file.
n When creating (c) a JAR file, this option normalizes the archive so that the
content is not affected by the packing and unpacking operations of the pack200(1)
command. Without this normalization, the signature of a signed JAR can become
invalid.
v Generates verbose output to standard output. See Examples.
0 (Zero) Creates (c) or updates (u) the JAR file without using ZIP compression.
-C dir
When creating (c) or updating (u) a JAR file, this option temporarily changes the
directory while processing files specified by the file operands. Its operation is
intended to be similar to the -C option of the UNIX tar utility.For example, the
following command changes to the classes directory and adds the Bar.class file from
that directory to my.jar:
jar uf my.jar -C classes Bar.class
The following command changes to the classes directory and adds to my.jar all files
within the classes directory (without creating a classes directory in the JAR
file), then changes back to the original directory before changing to the bin
directory to add Xyz.class to my.jar.
jar uf my.jar -C classes . -C bin Xyz.class
If classes contained files bar1 and bar2, then the JAR file will contain the
following after running the previous command:
% jar tf my.jar
META-INF/
META-INF/MANIFEST.MF
bar1
bar2
Xyz.class
-Joption
Sets the specified JVM option to be used when the JRE runs the JAR file. JVM
options are described on the reference page for the java(1) command. For example,
-J-Xms48m sets the startup memory to 48 MB.
OPERANDS
The following operands are recognized by the jar command.
file When creating (c) or updating (u) a JAR file, the file operand defines the path and
name of the file or directory that should be added to the archive. When extracting
(x) or listing the contents (t) of a JAR file, the file operand defines the path
and name of the file to be extrated or listed. At least one valid file or directory
must be specified. Separate multiple file operands with spaces. If the entrypoint,
jarfile, or manifest operands are used, the file operands must be specified after
them.
entrypoint
When creating (c) or updating (u) a JAR file, the entrypoint operand defines the
name of the class that should be the entry point for a standalone Java application
bundled into an executable JAR file. The entrypoint operand must be specified if
the e option is present.
jarfile
Defines the name of the file to be created (c), updated (u), extracted (x), or
viewed (t). The jarfile operand must be specified if the f option is present.
Omitting the f option and the jarfile operand instructs the jar command to accept
the JAR file name from stdin (for x and t) or send the JAR file to stdout (for c
and u).
When indexing (i) a JAR file, specify the jarfile operand without the f option.
manifest
When creating (c) or updating (u) a JAR file, the manifest operand defines the
preexisting manifest files with names and values of attributes to be included in
MANIFEST.MF in the JAR file. The manifest operand must be specified if the f option
is present.
@arg-file
To shorten or simplify the jar command, you can specify arguments in a separate
text file and pass it to the jar command with the at sign (@) as a prefix. When the
jar command encounters an argument beginning with the at sign, it expands the
contents of that file into the argument list.
An argument file can include options and arguments of the jar command (except the
-J options, because they are passed to the launcher, which does not support
argument files). The arguments within a file can be separated by spaces or newline
characters. File names within an argument file are relative to the current
directory from which you run the jar command, not relative to the location of the
argument file. Wild cards, such as the asterisk (*), that might otherwise be
expanded by the operating system shell, are not expanded.
The following example, shows how to create a classes.list file with names of files
from the current directory output by the find command:
find . -name '*.class' -print > classes.list
You can then execute the jar command and pass the classes.list file to it using the
@arg-file syntax:
jar cf my.jar @classes.list
An argument file can be specified with a path, but any file names inside the
argument file that have relative paths are relative to the current working
directory of the jar command, not to the path passed in, for example:
jar @dir/classes.list
NOTES
The e, f, and m options must appear in the same order on the command line as the
entrypoint, jarfile, and manifest operands, for example:
jar cmef myManifestFile MyMainClass myFile.jar *.class
EXAMPLES
Example 1 Adding All Files From the Current Directory With Verbose Output
% ls
1.au Animator.class monkey.jpg
2.au Wave.class spacemusic.au
3.au at_work.gif
% jar cvf bundle.jar *
added manifest
adding: 1.au(in = 2324) (out= 67)(deflated 97%)
adding: 2.au(in = 6970) (out= 90)(deflated 98%)
adding: 3.au(in = 11616) (out= 108)(deflated 99%)
adding: Animator.class(in = 2266) (out= 66)(deflated 97%)
adding: Wave.class(in = 3778) (out= 81)(deflated 97%)
adding: at_work.gif(in = 6621) (out= 89)(deflated 98%)
adding: monkey.jpg(in = 7667) (out= 91)(deflated 98%)
adding: spacemusic.au(in = 3079) (out= 73)(deflated 97%)
Example 2 Adding Files From Subdirectories
% ls -F
audio/ classes/ images/
% jar cvf bundle.jar audio classes images
added manifest
adding: audio/(in = 0) (out= 0)(stored 0%)
adding: audio/1.au(in = 2324) (out= 67)(deflated 97%)
adding: audio/2.au(in = 6970) (out= 90)(deflated 98%)
adding: audio/3.au(in = 11616) (out= 108)(deflated 99%)
adding: audio/spacemusic.au(in = 3079) (out= 73)(deflated 97%)
adding: classes/(in = 0) (out= 0)(stored 0%)
adding: classes/Animator.class(in = 2266) (out= 66)(deflated 97%)
adding: classes/Wave.class(in = 3778) (out= 81)(deflated 97%)
adding: images/(in = 0) (out= 0)(stored 0%)
adding: images/monkey.jpg(in = 7667) (out= 91)(deflated 98%)
adding: images/at_work.gif(in = 6621) (out= 89)(deflated 98%)
% ls -F
audio/ bundle.jar classes/ images/
Example 3 Listing the Contents of JAR
% jar tf bundle.jar
META-INF/
META-INF/MANIFEST.MF
audio/1.au
audio/2.au
audio/3.au
audio/spacemusic.au
classes/Animator.class
classes/Wave.class
images/monkey.jpg
images/at_work.gif
Example 4 Adding an Index
Use the i option when you split the interdependent classes for a stock trade application
into three JAR files: main.jar, buy.jar, and sell.jar. If you specify the Class-Path
attribute in the main.jar manifest, then you can use the i option to speed up the class
loading time for your application:
Class-Path: buy.jar sell.jar
jar i main.jar
An INDEX.LIST file is inserted to the META-INF directory. This enables the application
class loader to download the specified JAR files when it is searching for classes or
resources.
The application class loader uses the information stored in this file for efficient class
loading. To copy directories, first compress files in dir1 to stdout, then pipeline and
extract from stdin to dir2 (omitting the -f option from both jar commands):
(cd dir1; jar c .) | (cd dir2; jar x)
SEE ALSO
o pack200(1).
o The JAR section of The Java Tutorials at
http://docs.oracle.com/javase/tutorial/deployment/jar/index.html
JDK 8 21 November 2013 jar(1)
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On Apache
Under GNU General Public License
2024-04-19 21:39 @18.224.149.242 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)