Interesting. I'm a student, not much of a programmer, but learning. 

Both Java and Ruby are very new to me. (I've worked in Perl extensively and
C++ somewhat for several years)

>> What specifically do you like better about Java's IO library?
> Input and Output streams and writers, and the ability to fairly easily
chain 
>them.

This "chaining" is one of the things I HATE about Java. Learning io in Java
is a nightmare! Learning it in Ruby is fairly trivial.

Actually, learning anything in Ruby seems easier -- simpler and much more
intuitive -- than in Java. 

Just an opinion from a non-academic.