[ excerpt from developer's web site with modifications ]

Forward Error Correction (FEC) is an essential building block of
any satellite or IP multicast based content distribution system.
Our library is the fastest and most mature Java FEC library available.
It features:

o Fast multi-threaded I/O routines for encoding and decoding files
o FEC codec plugin interface 
o Cryptograhic hashes can be used for checking file integrity

WWW: http://onionnetworks.com/developers/