Java Threads, Second Edition

Chapter 8. Advanced Synchronization Topics

In this chapter, we will look into some of the more advanced issues related to data synchronization. When you write a Java program that makes use of several threads, issues related to data synchronization are those most likely to create difficulties in the design of the program, and errors in data synchronization are often the most difficult to detect, since they depend on events happening in a specific order. Often an error in data synchronization can be masked in the code by timing dependencies. You may notice some sort of data corruption in a normal run of your program, but when you run the program in a debugger or add some debugging statements to the code, the timing of the program is completely changed, and the data corruption no longer occurs.

Synchronization Terms

Programmers with a background in a particular threading system generally tend to use terms specific to that system to refer to some of the concepts we discuss in this chapter, and programmers without a background in certain threading systems will not necessarily understand the terms we choose to use. So here’s a comparison of particular terms you may be familiar with and how they relate to the terms in this chapter:

Barrier

A barrier is a rendezvous point for multiple threads: all threads must arrive at the barrier before any of them are permitted to proceed past the barrier. Java has no barrier class, but we implemented one in Chapter 5.

Condition variable

A condition ...