Dynamic (Adaptive) and (Regular) Huffman coding implementation in Java.
I've done this in autumn of 2002 as an assignment in "Data and File Structures" class. As I recall it worked but take that with a grain of salt and keep an eye on possible bugs if you intend to use it. Also at that time latest Java was 1.4.
DHuffman.java: Dynamic (Adaptive) implementation.
SHuffman.java: Regular implementation.