Book Image

Java 9 Regular Expressions

By : Anubhava Srivastava
Book Image

Java 9 Regular Expressions

By: Anubhava Srivastava

Overview of this book

Regular expressions are a powerful tool in the programmer's toolbox and allow pattern matching. They are also used for manipulating text and data. This book will provide you with the know-how (and practical examples) to solve real-world problems using regex in Java. You will begin by discovering what regular expressions are and how they work with Java. This easy-to-follow guide is a great place from which to familiarize yourself with the core concepts of regular expressions and to master its implementation with the features of Java 9. You will learn how to match, extract, and transform text by matching specific words, characters, and patterns. You will learn when and where to apply the methods for finding patterns in digits, letters, Unicode characters, and string literals. Going forward, you will learn to use zero-length assertions and lookarounds, parsing the source code, and processing the log files. Finally, you will master tips, tricks, and best practices in regex with Java.
Table of Contents (15 chapters)
Title page
About the Author
About the Reviewer
Customer Feedback
Free Chapter
Getting Started with Regular Expressions

Chapter 8. Regular Expression Pitfalls, Optimization, and Performance Improvements

Regular expressions, if not written well may perform poorly. They may run slowly, and when they are executed frequently in some code, they may be the source of high CPU utilization. To avoid these problems, regular expressions have to be crafted carefully, understanding the possible pitfalls, and they also have to be tested thoroughly. We will be covering the following topics in this chapter:

  • Common pitfalls and ways to avoid them while writing regular expressions
  • How to test your regex functionality and performance
  • Optimization and performance enhancing tips
  • Catastrophic backtracking and how to avoid it