Introduction to Regular Expressions in Java

Regular expressions (regex) are sequences of characters that define search patterns. They are incredibly powerful tools for searching, validating, and manipulating text. In Java, regex is used extensively through the Pattern and Matcher classes. For beginners, it is important to understand the various components of a regex, such as meta characters, quantifiers, and flags, and how these elements work together to form a pattern.

Before we learn to create and use the regular expression, let's learn a few key terms used in creating the regular expression.