Andrew Glover has written very nice Ruby language article for IBM’s developerWorks titled Ruby off the Rails . Its intended as an introduction to Ruby specifically for Java programmers.
What I particularly liked about this article was the way he compared the Java way to the Ruby way with specific and realistic code. This really illustrates the advantage that Ruby has is some very concrete ways.
Take a look at the Java code for the Definition and Word classes. How long does it take to understand how the code works? Now do the same thing with the Ruby implementation of these same two classes.
Ruby is much more concise than Java. The lower level of “code noise” makes Ruby easier to comprehend at a glance. I know both languages very well, and I can tell you from experience that this makes both writing and reading code much more productive.
If you are a Java programmer who is curious about Ruby, then this article is for you.