Is "Java Concurrency In Practice" still valid?
I bought this book in 2013. I had very serious doubts that it would be current and useful given that this edition was published so long ago. The technology world moves quickly, and software technology even faster. Even so, this book is foundational. The concepts and practices that are discussed are more underpinnings for good software design and engineering than updates on the latest and greatest API's. This book has been indispensable, and I am glad that I got it before I had decided to write even a single line of concurrent code. It's probably saved me countless hours.
Yes definitely it's still valid, but I will recommend in addition or as an introduction The Well-Grounded Java Developer a well written book with a chapter on modern Java concurrency techniques and nicely done examples.
Yes, it's still valid in my mind. There isn't big change in this area from 6 to 7. Fork-join is a new feature, which is very suitable for divide-and-conquer type of problems. But all the existing stuff inside the book, such as synchronization, volatile, servlet, are still very valid.
While my perspective may be biased, my current intention for updating the book would be almost strictly additive, covering fork-join, parallel decomposition, and the new parallel bulk data operations coming in Java SE 8.
EDIT 2020: ... and Project Loom.
EDIT 2021: ... and Project Loom :)
EDIT 2022: ... and Project Loom !