# Package java.util.regex

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

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  MatchResult | The result of a match operation.

- Class Summary
  Class | Description
  --- | ---
  Matcher | An engine that performs match operations on a ``character sequence`` by interpreting a `Pattern`.
  Pattern | A compiled representation of a regular expression.

- Exception Summary
  Exception | Description
  --- | ---
  PatternSyntaxException | Unchecked exception thrown to indicate a syntax error in a regular-expression pattern.

## Package java.util.regex Description

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.

## Related Documentation

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

Since:
  1.4

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