What is the usage of Matcher in Java?

In Java, Matcher is an engine used to perform regular expression matching operations. It is typically used in conjunction with the Pattern class, which compiles the regular expression, while Matcher is used to carry out matching operations within a given input string.

The Matcher class offers a variety of methods to perform different types of matching operations. Here are some commonly used Matcher methods:

1. matches(): attempts to match the entire input sequence against the regular expression. If the entire sequence matches successfully, it returns true; otherwise, it returns false.
2. find(): attempts to find the next subsequence in the input sequence that matches the regular expression. If a matching subsequence is found, it returns true; otherwise, it returns false.
3. group(): returns the input subsequence that was last matched in the previous match operation.
4. start(): Returns the starting index of the last matched operation’s substring.
5. end(): Returns the ending index of the last matched substring in the previous matching operation.
6. replaceFirst() function replaces the first subsequence in the input sequence that matches the regular expression.
7. replaceAll() replaces all subsequences in the input sequence that match the regular expression.
8. reset(): resets the matching state of the Matcher object.

These methods are just a small part of what the Matcher class offers; there are many more methods available for use. Using the Matcher class can help us easily perform operations like string matching, searching, and replacing.