pack200(1) pack200(1)
NAME
pack200 - JAR Packing tool
SYNOPSIS
pack200 [ OPTIONS ] output-file JAR-file
PARAMETERS
The options may be in any order. The last option on the command line or in a properties file super-sedes supersedes
sedes all previously specified options. For a discussion of the options, see OPTIONS below.
OPTIONS see OPTIONS below.
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 compressed packed files are highly compressed JARs that can be
directly deployed, saving bandwidth and reducing download time.
The pack200 tool uses several options to fine-tune and set the compression engine.
Typical usage:
% pack200 myarchive.pack.gz myarchive.jar
In this example, the myarchive.pack.gz is produced, using the default pack200 and gzip 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-packed.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 also use a corresponding decompressor.
% pack200 --no-gzip myarchive.pack myarchive.jar
-G --strip-debug
Strips the attributes used for debugging, from the output. These include SourceFile, LineNum-berTable, LineNumberTable,
berTable, LocalVariableTable and LocalVariableTypeTable. Removing these attributes reduces
the size of both downloads and installations but reduces the usefulness of debuggers.
-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 special 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 transmit-ted transmitted
ted in the segment, along with the size of its name and other transmitted properties.
The default is 1000000 (a million bytes). This allows input JAR files of moderate size to be
transmitted in one segment. It also puts a limit on memory requirements for packers and
unpackers.
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 produce somewhat larger size and faster com-pression compression
pression 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 reasonable 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 accordingly in the output ar-chive, archive,
chive, 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 avail-able available
able entries in the original archive, or the latest modification time of all the avail-able available
able entries in that segment. This single value will be transmitted as part of the seg-ment segment
ment 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 sin-gle single
gle date.
keep
Preserve modification times observed in the input JAR. (This is the default.)
-Pfile -pass-file=file
Indicates that a file should be passed through byte-wise with no compression. By repeating the
option, multiple files may be specified,. There is no pathname transformation, except that
the system file separator 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, ie. 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 explanation.
strip:
The attribute will be dropped. Note: removing the VM required attributes may cause Class
Loader failures.
pass:
Upon encountering this attribute, the entire class will be transmitted as though it is a
resource. (This is the default.)
-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. For example --class-attribute=SourceFile=RUH. --classattribute=SourceFile=RUH.
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 the VM required attributes may cause Class Loader failures.
pass
upon encountering this attribute, the entire class will be transmitted as though it is a
resource.
Example --class-attribute=CompilationID=pass, will cause the classfile containing this
attribute to be passed through, without further action by the packer.
-fpack.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
% cat 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
Non-Standard Options
-v --verbose Outputs minimal messages, multiple specification of this option will output more
verbose messages.
-q --quiet Quiet operation with no messages.
-lfilename --log-file=filename
A log file to output messages.
-Joption Passes option to the Java launcher called by pack200. For example, -J-Xms48m -JXms48m
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 applications written in
Java.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
SEE ALSO
unpack200(1), jar(1), jarsigner(1), attributes(5)
For API specification and other related information:
http://java.sun.com/j2se/5.0/docs
http://java.sun.com/j2se/5.0/docs/guide/deployment/deployment-guide/pack200.html
NOTES:
This command should not be confused with pack(1). They are distinctly separate products.
The J2SE API Specification provided with the JDK release is the superseding
authority, in case of discrepancies.
14 July 2004 pack200(1)
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