The Java Tutorials have been written for JDK 8. Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.
See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.
Lesson: Regular Expressions
This lesson explains how to use the
java.util.regex
API for pattern matching with regular expressions. Although the syntax accepted by this package is similar to the
Perl programming language, knowledge of Perl is not a prerequisite. This lesson starts with the basics, and gradually builds to cover more advanced techniques.
-
Introduction
- Provides a general overview of regular expressions. It also introduces the core classes that comprise this API.
-
Test Harness
- Defines a simple application for testing pattern matching with regular expressions.
-
String Literals
- Introduces basic pattern matching, metacharacters, and quoting.
-
Character Classes
- Describes simple character classes, negation, ranges, unions, intersections, and subtraction.
-
Predefined Character Classes
- Describes the basic predefined character classes for whitespace, word, and digit characters.
-
Quantifiers
- Explains greedy, reluctant, and possessive quantifiers for matching a specified expression x number of times.
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Capturing Groups
- Explains how to treat multiple characters as a single unit.
-
Boundary Matchers
- Describes line, word, and input boundaries.
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Methods of the Pattern Class
- Examines other useful methods of the
Pattern
class, and explores advanced features such as compiling with flags and using embedded flag expressions.
-
Methods of the Matcher Class
- Describes the commonly-used methods of the
Matcher
class.
-
Methods of the PatternSyntaxException Class
- Describes how to examine a
PatternSyntaxException
.
-
Additional Resources
- To read more about regular expressions, consult this section for additional resources.