Learn Java Programming - Regex Character Classes Part 2 Tutorial

In this tutorial we'll build on concepts learned from my Regex Character Classes Part 1 Tutorial. I will be covering unions, intersections, and subtraction in this tutorial.
Unions · nested character classes contained inside square brackets
Intersections · nested character classes contained inside square brackets separated with &&
Subtraction · nested character classes contained inside square brackets separated with && with at least one character class containing the "^" negation metacharacter