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jgz - Overview

The jgz library is an implementation in Java of the DEFLATE compression algorithm, and gzip and zlib file formats. Current version is 0.2 (considered beta).

Jgz has been written by Thomas Pornin. Comments and questions may be addressed by e-mail: <pornin@bolet.org>


The DEFLATE algorithm is specified in RFC 1951; it is a general purpose lossless compression algorithm which is used in several formats, including ZIP archives and PNG images. It is also the core of the gzip compression software which is quite ubiquitous in the Unix world.

The reference implementation of DEFLATE is a library called zlib. Its code is used in many software packages, including the gzip utility. It has undergone many years of testing and tweaking, and is considered very stable and quite optimized. Zlib provides an API for the DEFLATE algorithm itself; it also supports encoding and decoding in two file formats:

Both file formats are simple wrappers around the output of DEFLATE, and add some metadata and checksums.

Jgz is an independant implementation of DEFLATE, and the zlib and gzip file formats, entirely written in the Java programming language. The implementation is compatible with quite old Java virtual machines (JDK 1.1) and limited Java platforms (J2ME with MID profile, for mobile phones).

Last modified: Saturday, August 18, 2007 9:11:56 AM CEST