Core Java for the Impatient, 4th Edition

An Essential Guide to the Core Language and Libraries--Updated for Java 21

Modern Java introduces major enhancements that impact the core language and APIs at the heart of the Java platform. Many old Java idioms are no longer needed, and new features and programming paradigms can make you far more effective. However, navigating these changes can be challenging.

Core Java for the Impatient, Fourth Edition, is a complete guide that reflects all changes through Java SE 21, Oracle's latest Long-Term Support (LTS) release. Written by Cay S. Horstmann--author of the classic two-volume Core Java--this concise tutorial offers a faster, easier pathway for learning modern Java.

Horstmann covers everything working developers need to know, including the powerful concepts of lambda expressions and streams, modern constructs such as records and sealed classes, and sophisticated concurrent programming techniques. Given the size and scope of Java 21, there's plenty to cover. As in previous editions, everything is presented in small chunks organized for quick access and easy understanding, with plenty of practical insights and sample code to help you quickly apply all that's new.

• Test code as you create it with JShell
• Improve your object-oriented design with records and sealed classes
• Effectively use text blocks, switch expressions, and pattern matching
• Understand functional programming with lambda expressions
• Streamline and optimize data management with the Streams API
• Use structured techniques, threadsafe data structures, and virtual threads for effective concurrent programming
• Work with the modularized Java API and third-party modules
• Take advantage of API improvements for working with collections, input/output, regular expressions, and processes

Whether you're an experienced developer just getting started with modern Java or have been programming with Java for years, this guide will help you write more robust, efficient, and secure Java code.

Core Java for the Impatient provides accessible coverage of Java features that will enable readers to

• Master foundational techniques, idioms, and best practices for writing superior Java code
• Leverage the power of input/output
• Improve performance and efficiency
• Fully utilize multicore processors with Java's improved concurrency

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Cay S. Horstmann is author of Core Java, Volumes I and II, Thirteenth Edition (Pearson, 2025), Modern JavaScript for the Impatient (Addison-Wesley, 2020), and Scala for the Impatient, Third Edition (Addison-Wesley, 2023). He has written more than a dozen other books for professional programmers and computer science students. He is an emeritus professor of computer science at San Jose State University and a Java Champion.