So I can take say somebody's Java library, which they designed and put together, and rewrite it in BlitzMax and then say this BlitzMax library is copyrighted by me as the author, even if most of the code is almost the same as the Java code?
It's hard to say with any degree of certainty, because copyright laws are archaic. However the author does traditionally have the right to translate his own work - if that is interpreted litterally by a court, you could be in trouble.Other wise, I believe that it would qualify as a derived work and thus be subject to fair use. However since the author has explicitly declared it is not to be used in a commercial product, I would see if I could find similar source code in the public domain - just in case.