Added in API level 1

java.util.regex

Classes for matching character sequences against patterns specified by regular expressions.

An instance of the Pattern class represents a regular expression that is specified in string form in a syntax similar to that used by Perl.

Instances of the Matcher class are used to match character sequences against a given pattern. Input is provided to matchers via the CharSequence interface in order to support matching against characters from a wide variety of input sources.

Unless otherwise noted, passing a null argument to a method in any class or interface in this package will cause a NullPointerException to be thrown.

An excellent tutorial and overview of regular expressions is Mastering Regular Expressions, Jeffrey E. F. Friedl, O'Reilly and Associates, 1997.

Interfaces

MatchResult The result of a match operation. 

Classes

Matcher An engine that performs match operations on a character sequence by interpreting a Pattern. 
Pattern A compiled representation of a regular expression. 

Exceptions

PatternSyntaxException Unchecked exception thrown to indicate a syntax error in a regular-expression pattern.