As processors become faster and multiprocessor systems become cheaper, the need to take advantage of multithreading in order to achieve full hardware resource utilization only increases the importance of being able to incorporate concurrency in a wide variety of application categories. For many developers, concurrency remains a mystery. Developing, testing and debugging multithreaded programs is extremely difficult because concurrency hazards do not manifest themselves uniformly or reliably. This book is intended to be neither an introduction to concurrency (any threading chapter in an 'intro' book does that) nor is it an encyclopedic reference of All Things Concurrency (that would be Doug Lea's Concurrent Programming in Java). Instead, this title is a combination of concepts, guidelines, and examples intended to assist developers in the difficult process of understanding concurrency and its new tools in J2SE 5.0.
Filled with contributions from Java gurus such as Josh Bloch, David Holmes and Doug Lea, this book provides any Java programmers with the basic building blocks they need to gain a basic understanding of concurrency and its benefits.
Features and Benefits
A how-to companion to Doug Lea's 'Concurrent Programming in Java', this book is the only authorative and practical guide to Java Concurrency
° Powerhouse author team with contributions from Doug Lea, Josh Bloch and David Holmes
° A practical, hands-on, example-driven guide for every working Java programmer
° Based on J2SE 5.0 which includes many new concurrency features that make concurrency development much more accesible (and necessary)
Table of Contents
top
Listings
xii
Preface
xvii
Chapter 1: Introduction
1
1.1
A (very) brief history of concurrency
1
1.2
Benefits of threads
3
1.3
Risks of threads
5
1.4
Threads are everywhere
9
Part I: Fundamentals
13
Chapter 2: Thread Safety
15
2.1
What is thread safety?
17
2.2
Atomicity
19
2.3
Locking
23
2.4
Guarding state with locks
27
2.5
Liveness and performance
29
Chapter 3: Sharing Objects
33
3.1
Visibility
33
3.2
Publication and escape
39
3.3
Thread confinement
42
3.4
Immutability
46
3.5
Safepublication
49
Chapter 4: Composing Objects
55
4.1
Designing a thread-safe class
55
4.2
Instance confinement
58
4.3
Delegating thread safety
62
4.4
Adding functionality to existing thread-safe classes
71
4.5
Documenting synchronization policies
74
Chapter 5: Building Blocks
79
5.1
Synchronized collections
79
5.2
Concurrent collections
84
5.3
Blocking queues and the producer-consumer pattern
87
5.4
Blocking and interruptible methods
92
5.5
Synchronizers
94
5.6
Building an efficient, scalable result cache
101
Part II: Structuring Concurrent Applications
111
Chapter 6: Task Execution
113
6.1
Executing tasks in threads
113
6.2
The Executor framework
117
6.3
Finding exploitable parallelism
123
Chapter 7: Cancellation and Shutdown
135
7.1
Task cancellation
135
7.2
Stopping a thread-based service
150
7.3
Handling abnormal thread termination
161
7.4
JVM shutdown
164
Chapter 8: Applying Thread Pools
167
8.1
Implicit couplings between tasks and execution policies
167
8.2
Sizing thread pools
170
8.3
Configuring ThreadPoolExecutor
171
8.4
Extending ThreadPoolExecutor
179
8.5
Parallelizing recursive algorithms
181
Chapter 9: GUI Applications
189
9.1
Why are GUIs single-threaded?
189
9.2
Short-running GUI tasks
192
9.3
Long-running GUI tasks
195
9.4
Shared data models
198
9.5
Other forms of single-threaded subsystems
202
Part III: Liveness, Performance, and Testing
203
Chapter 10: Avoiding Liveness Hazards
205
10.1
Deadlock
205
10.2
Avoiding and diagnosing deadlocks
215
10.3
Other liveness hazards
218
Chapter 11: Performance and Scalability
221
11.1
Thinking about performance
221
11.2
Amdahl's law
225
11.3
Costs introduced by threads
229
11.4
Reducing lock contention
232
11.5
Example: Comparing Map performance
242
11.6
Reducing context switch overhead
243
Chapter 12: Testing Concurrent Programs
247
12.1
Testing for correctness
248
12.2
Testing for performance
260
12.3
Avoiding performance testing pitfalls
266
12.4
Complementary testing approaches
270
Part IV: Advanced Topics
275
Chapter 13: Explicit Locks
277
13.1
Lock and ReentrantLock
277
13.2
Performance considerations
282
13.3
Fairness
283
13.4
Choosing between synchronized and ReentrantLock
285
13.5
Read-write locks
286
Chapter 14: Building Custom Synchronizers
291
14.1
Managing state dependence
291
14.2
Using condition queues
298
14.3
Explicit condition objects
306
14.4
Anatomy of a synchronizer
308
14.5
AbstractQueuedSynchronizer
311
14.6
AQS in java.util.concurrent synchronizer classes
314
Chapter15: Atomic Variables and Nonblocking Synchronization
319
15.1
Disadvantages of locking
319
15.2
Hardware support for concurrency
321
15.3
Atomic variable classes
324
15.4
Nonblocking algorithms
329
Chapter 16: The Java Memory Model
337
16.1
What is a memory model, and why would I want one?
337
16.2
Publication
344
16.3
Initialization safety
349
Appendix A: Annotations for Concurrency
353
A.1
Class annotations
353
A.2
Field andmethod annotations
353
Bibliography
355
Index
359
