Interval halving (Bisection) method in Scala (OOP and FP styles)

I just picked up an old college textbook named Applied Numerical Analysis, and curious to see what the Interval Halving method (also known as the Bisection Method) would look like in Scala, I decided to code it up. Considering that Scala is similar to the Java programming language, if anyone else needs the Interval-Halving method in Java, this code can easily be adapted to Java as well.

A Java email address validation class

I thought I'd share the source code for my Java email address validator class. I'm not sure if there's a big need for it ... I wrote it a long time ago, and I think I created it because Java's javax.mail.internet.InternetAddress class wasn't validating email addresses as deeply as I wanted it to. For instance, I think it would allow the string "fred" to be a valid email address, but on the internet you really want to see something like "". So I think that's where this class comes from.