"Endian" refers to how a given CPU reads bytes in a word: left to right (like Motorola or SPARC processors) or right to left (like Intel x86 processors). Here's a good link:
The reason ByteOrder works is that you happen to be using Java "nio" (instead of, say, Readers, Writers or RandomAccess file types). If your application can easily use nio, great. Otherwise, you'll probably need a more general ("bit twiddling") solution.
IMHO .. pSM