Java Concurrency in Practice

Chapter 4. Composing Objects

So far, we've covered the low-level basics of thread safety and synchronization. But we don't want to have to analyze each memory access to ensure that our program is thread-safe; we want to be able to take thread-safe components and safely compose them into larger components or programs. This chapter covers patterns for structuring classes that can make it easier to make them thread-safe and to maintain them without accidentally undermining their safety guarantees.

4.1. Designing a Thread-safe Class

While it is possible to write a thread-safe program that stores all its state in public static fields, it is a lot harder to verify its thread safety or to modify it so that it remains thread-safe than one that uses encapsulation ...