Using Java as a regular expression flavor, in this chapter, we will go a bit deeper and learn in detail about anchors, quantifiers, boundary matchers, all the available character classes, negated character classes, predefined character classes, and character classes escaping rules, using Java as a reference point. You will also learn Unicode text matching, using regular expressions in Java. We will also cover greedy versus non-greedy (lazy matching) and the change of regular expression behavior with lazy matching.

We will cover the following topics in this chapter:

• Anchors and quantifiers
• Boundary matchers
• Character classes
• Regex escaping rules
• Escaping inside character classes
• Negated character classes
• Predefined character classes
• Unicode characters matching
• Greedy quantifiers
• Lazy quantifiers
• Possessive quantifiers
• Various embedded modes in regular expressions and their meaning
• Enabling/disabling regular expression modes inside the regex