pack200(1)pack200(1)Namepack200 - JAR Packing tool
SYNOPSISpack200 [ options ] output-file JAR-file
Options may be in any order. The last option on the command line or in
a properties file supersedes all previously specified options.
options
Command-line options.
output-file
Name of the output file.
JAR-file
Name of the input file.
DESCRIPTION
The pack200 tool is a Java application that transforms a JAR file into
a compressed pack200 file using the Java gzip compressor. The pack200
files are highly compressed files that can be directly deployed, saving
bandwidth and reducing download time.
The pack200 tool uses several options to fine-tune and set the compres‐
sion engine.
Typical usage:
% pack200 myarchive.pack.gz myarchive.jar
In this example, myarchive.pack.gz is produced using the default
pack200 settings.
OPTIONS-r --repack
Produces a JAR file by packing the file myarchive.jar and unpacking it.
The resulting file can be used as an input to the jarsigner(1) tool.
% pack200--repack myarchive-packer.jar myarchive.jar
% pack200--repack myarchive.jar
-g --no-gzip
Produces a pack200 file. With this option a suitable compressor must be
used, and the target system must use a corresponding decompresser.
% pack200--no-gzip myarchive.pack myarchive.jar
-G --strip-debug
Strips attributes used for debugging from the output. These include
SourceFile, LineNumberTable, LocalVariableTable and LocalVariableType‐
Table. Removing these attributes reduces the size of both downloads and
installations but reduces the usefulness of debuggers.
--keep-file-order
Preserve the order of files in the input file; this is the default
behavior.
-O --no-keep-file-order
The packer will reorder and transmit all elements. Additionally, the
packer may remove JAR directory names. This will reduce the download
size; however, certain JAR file optimizations, such as indexing, may
not work correctly.
-Svalue --segment-limit=value
The value is the estimated target size N (in bytes) of each archive
segment. If a single input file requires
more than N bytes, it will be given its own archive segment. As a spe‐
cial case, a value of -1 will produce a single large segment with all
input files, while a value of 0 will produce one segment for each
class. Larger archive segments result in less fragmentation and better
compression, but processing them requires more memory.
The size of each segment is estimated by counting the size of each
input file to be transmitted in the segment, along with the size of its
name and other transmitted properties.
The default is -1, which means the packer will always create a single
segment output file. In cases where extremely large output files are
generated, users are strongly encouraged to use segmenting or break up
the input file into smaller JARs.
A 10MB JAR packed without this limit will typically pack about 10%
smaller, but the packer may require a larger Java heap (about ten times
the segment limit).
-Evalue --effort=value
If the value is set to a single decimal digit, the packer will use the
indicated amount of effort in compressing the archive. Level 1 may pro‐
duce somewhat larger size and faster compression speed, while level 9
will take much longer but may produce better compression. The special
value 0 instructs the packer to copy through the original JAR file
directly with no compression. The JSR 200 standard requires any
unpacker to understand this special case as a pass-through of the
entire archive.
The default is 5, investing a modest amount of time to produce reason‐
able compression.
-Hvalue --deflate-hint=value
Overrides the default, which preserves the input information, but may
cause the transmitted archive to be larger. The possible values are:
true
false
In either case, the packer will set the deflation hint accord‐
ingly in the output archive, and will not transmit the individual
deflation hints of archive elements.
keep
Preserve deflation hints observed in the input JAR. (This is the
default.)
-mvalue --modification-time=value
The possible values are:
latest
The packer will attempt to determine the latest modification
time, among all the available entries in the original archive, or
the latest modification time of all the available entries in that
segment. This single value will be transmitted as part of the
segment and applied to all the entries in each segment. This can
marginally decrease the transmitted size of the archive at the
expense of setting all installed files to a single date.
keep
Preserves modification times observed in the input JAR. (This is
the default.)
-Pfile --pass-file=file
Indicates that a file should be passed through bytewise with no com‐
pression. By repeating the option, multiple files may be specified.
There is no pathname transformation, except that the system file sepa‐
rator is replaced by the JAR file separator "/". The resulting file
names must match exactly as strings with their occurrences in the JAR
file. If file is a directory name, all files under that directory will
be passed.
-Uaction --unknown-attribute=action
Overrides the default behavior; i.e., the classfile containing the
unknown attribute will be passed through with the specified action. The
possible values for actions are:
error
The pack200 operation as a whole will fail with a suitable expla‐
nation.
strip
The attribute will be dropped. Note: Removing the required VM
attributes may cause Class Loader failures.
pass
Upon encountering this attribute, the entire class will be trans‐
mitted as though it is a resource.
-Cattribute-name=layout --class-attribute=attribute-name=action
-Fattribute-name=layout --field-attribute=attribute-name=action
-Mattribute-name=layout --method-attribute=attribute-name=action
-Dattribute-name=layout --code-attribute=attribute-name=action
With the above four options, the attribute layout can be specified for
a class entity, such as Class attribute, Field attribute, Method
attribute, and Code attribute. The attribute-name is the name of the
attribute for which the layout or action is being defined. The possible
values for action are:
some-layout-string
The layout language is defined in the JSR 200 specification.
Example: --class-attribute=SourceFile=RUH
error
Upon encountering this attribute, the pack200 operation will fail
with a suitable explanation.
strip
Upon encountering this attribute, the attribute will be removed
from the output. Note: removing VM-required attributes may cause
Class Loader failures.
Example: --class-attribute=CompilationID=pass will cause the class file
containing this attribute to be passed through without further action
by the packer.
-f pack.properties --config-file=pack.properties
A configuration file, containing Java properties to initialize the
packer, may be specified on the command line.
% pack200-f pack.properties myarchive.pack.gz myarchive.jar
% more pack.properties
# Generic properties for the packer.
modification.time=latest
deflate.hint=false
keep.file.order=false
# This option will cause the files bearing new attributes to
# be reported as an error rather than passed uncompressed.
unknown.attribute=error
# Change the segment limit to be unlimited.
segment.limit=-1
-v --verbose
Outputs minimal messages. Multiple specification of this option will
output more verbose messages.
-q --quiet
Specifies quiet operation with no messages.
-lfilename --log-file=filename
Specifies a log file to output messages.
-? -h --help
Prints help information about this command.
-V --version
Prints version information about this command.
-Joption
Passes option to the Java launcher called by pack200. For example,
-J-Xms48m sets the startup memory to 48 megabytes. Although it does not
begin with -X, it is not a standard option of pack200. It is a common
convention for -J to pass options to the underlying VM executing appli‐
cations written in Java.
EXIT STATUS
The following exit values are returned:
0 for successful completion;
>0 if an error occurs.
SEE ALSO
o unpack200(1)
o Java SE Documentation @
http://docs.oracle.com/javase/7/docs/index.html
o Java Deployment Guide - Pack200 @
http://docs.oracle.com/javase/7/docs/technotes/guides/deploy‐
ment/deployment-guide/pack200.html
o jar(1) - Java Archive Tool
o jarsigner(1) - JAR Signer tool
o attributes(5) man page
NOTES
This command should not be confused with pack(1). They are distinctly
separate products.
The Java SE API Specification provided with the JDK is the superseding
authority, in case of discrepancies.
16 Mar 2012 pack200(1)
