A regular expression describes a pattern in a sequence of characters. A regular expression is a string that describes a character sequence.
We can then use pattern to
The java.util.regex package supports regular expression processing.
The general description in a regular expression called a pattern, can be used to find matches in other character sequences.
Regular expressions can specify wildcard characters, sets of characters, and various quantifiers.
We can specify a regular expression that represents a general form that can match several different specific character sequences.
There are two classes that support regular expression processing:
Pattern and Matcher.
These classes work together: use Pattern to define a regular expression.
and match the pattern against another sequence using Matcher.