This library contains a parallelized GZIP implementation which is a high performance drop-in replacement for the standard java.util.zip classes. It is a pure Java equivalent of the pigz parallel compresssor.
The performance of ParallelGZIPOutputStream is excellent: it scales linearly with the number of cores, and spends 95% of all thread time in the native compression routines on 24 and c32-core Xeon systems.
ParallelGZIPOutputStream has exactly the same memory contract as GZIPOutputStream: it extends FilterOutputStream. If a single thread writes data into the compressor, it will write compressed data to the underlying output stream on the same thread without any externally visible synchronization or flush calls. The user never needs to know or change anything as a result of the parallelism.
Currently, ParallelGZIPInputStream is a subclass of the standard GZIPInputStream, but parallelism may be added in future.
The JavaDoc API is available.
I needed this at work, but I was inspired to publish it by Paul Eggert's CS131 coursework at http://www.cs.ucla.edu/classes/fall11/cs131/hw/hw3.html - I wonder what grade I will get.