figured out how to get java to find my files.
Arraylist approach to counting frequency doesn't work.
It would have saved some space and had only a bit worse running time than a pure array.
array approach would take ridiculous amounts of RAM, most of which would be wasted.
linkedlist approach would save space but still require a custom implementation and the running time would be awful.
compromising with an AVL tree so that I can insert new huffman trees in order by key in logarithmic time, then find them again by key in logarithmic time.
this way each new character found is an insertion, and each access when an old character is found runs in logarithmic time too.
the data set for this only grows with the number of different characters encountered.