Java in Action

"Java in Action" is a practical guide to modern Java development, focusing on real-world tasks and advanced language features. The book is aimed at developers already familiar with Java basics and helps them transition from writing simple educational examples to creating professional, efficient, and maintainable code.

The main focus is on functional programming in Java, lambda expressions, Stream API, working with dates and time (Java 8+), Optional, CompletableFuture, and new collections. The author thoroughly examines how to apply these tools for data processing, building asynchronous systems, and improving application architecture. Separate chapters are dedicated to testing with JUnit 5, refactoring legacy code, working with databases via JDBC and JPA, as well as the basics of multithreading and concurrency.

The reader will learn how to write clean, modular code, avoid common mistakes, effectively use the capabilities of modern Java (up to version 11 inclusive), optimize performance, and create scalable applications. The book contains many code examples, practical exercises, and analysis of real-world scenarios from industrial development.

Chapter content includes: introduction to lambda expressions and functional interfaces; Stream API: filtering, mapping, reduction; working with Optional to avoid NullPointerException; asynchronous programming with CompletableFuture; new Date/Time API; improved collections and Maps; testing with JUnit 5 and Mockito; refactoring and design patterns in a functional style; multithreading and parallel streams; working with databases (JDBC, JPA); project building with Maven and Gradle; profiling and optimization.

Why you should read it: the book is written in lively language, without excessive academicism, with an emphasis on practice. It will help a mid-level Java developer rise to a new level, master modern language idioms, and learn to write code that is easy to maintain and evolve. This is a desktop guide for those who want to use Java truly effectively.