Effective Java, 3rd Ed. - Joshua Bloch - 2018 - The definitive guide to writing robust, idiomatic Java.
Java Concurrency in Practice - Brian Goetz et al. - 2006 - The classic on writing safe and scalable concurrent Java code; still unsurpassed.
Modern Java in Action, 2nd Ed. - Raoul-Gabriel Urma, Mario Fusco, Alan Mycroft - 2019 - Lambdas, streams, modules, reactive, and records; the Java 17+ way.
Spring in Action, 6th Ed. - Craig Walls - 2022 - The definitive practical guide to the Spring ecosystem.
Java in a Nutshell, 8th Ed. - Benjamin J. Evans, Jason Clark, David Flanagan - 2023 - Compact reference through Java 17; language, concurrency, collections, I/O.
Head First Java, 3rd Ed. - Kathy Sierra, Bert Bates, Trisha Gee - 2022 - Brain-friendly intro to Java; OOP, syntax, and real-world examples.
Real-World Java - Victor Grazi & Jeanne Boyarsky - 2025 - Practical tools and frameworks: Spring, Git, testing, observability, and the modern Java ecosystem.
Head First Design Patterns, 2nd Ed. - Eric Freeman, Elisabeth Robson - 2020 - Design patterns with Java; visual and memorable (applies beyond Java).