Regular expressions are widely used to match strings of text. For example, the POSIX {{grep}} utility supports regular expressions for finding patterns in the specified text. For introductory information on regular expressions, see the Java Tutorials \[[Tutorials 08|AA. Java References#TutorialsBibliography#Tutorials 08]\]. The {{java.util.regex}} package provides the {{Pattern}} class that encapsulates a compiled representation of a regular expression and the {{Matcher}} class that is an engine which interprets and uses a {{Pattern}} to perform matching operations on a {{CharacterSequence}}. | 