At4J provides Java support for reading and creating Zip and Tar archives. It also comes with third-party compression libraries for bzip2 and LZMA support. At4J supports more Zip capabilities and compression methods than Java's built-in Zip classes, such as Unix file metadata and bzip2 compression.
The Lempel-Ziv Markov-chain Algorithm is a very effective and relatively fast compression technique used in the ‘7z’ format of the 7-Zip archiver. This Package provides provides implementations of LzmaInputStream and LzmaOutputStream that interact with underlying LZMA encoders and decoders running in separate threads.