Analysis of Java Concurrency Framework: Systematically Organize Your Concurrency Knowledge
When learning Java concurrency programming, we often encounter many fragmented knowledge points that lack a comprehensive framework, making it easy for us to forget and confuse. Therefore, to better master Java concurrency programming, it is better to systematically organize this knowledge from a global perspective. The concurrency-related content in Java can be learned from the java.util.concurrent package. Understanding these classes also means understanding a large part of Java concurrency knowledge. Next, I will analyze these classes to help everyone better understand the Java concurrency framework.
1. Executor Framework (Executors)
The executor framework is a core component of Java concurrency programming. It provides functions such as thread pool management and task scheduling. Through the executor framework, we can submit tasks to the thread pool for execution without managing the thread's lifecycle ourselves.
The main classes are Executor, ExecutorService, ScheduledExecutorService, AbstractExecutorService, ThreadPoolExecutor, ScheduledThreadPoolExecutor, Executors, and ThreadFactory.
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2. Future and Asynchronous Computing
The Future interface and Callable interface are used to represent the results of asynchronous computing. The Future provides functions such as querying computing results, canceling computing tasks, and waiting for computing completion. The Callable interface is a task with a return value.
The main classes are Future, Callable, RunnableFuture, FutureTask, CompletionService, ExecutorCompletionService, CompletableFuture, and CompletionStage.
3. Blocking Queue
The blocking queue is a commonly used data structure in Java concurrency programming, mainly used to implement the producer-consumer pattern. The producer puts data into the queue, and the consumer takes data out of the queue. When the queue is full, the producer blocks and waits; when the queue is empty, the consumer blocks and waits.
The main classes are BlockingQueue, ArrayBlockingQueue, LinkedBlockingQueue, PriorityBlockingQueue, DelayQueue, SynchronousQueue, and TransferQueue.
4. Blocking Deque
The blocking deque is an extension of the blocking queue, which supports insertion and removal operations at both ends of the queue.
The main classes are BlockingDeque and LinkedBlockingDeque.
5. Concurrent Collection
The concurrent collection in Java concurrency programming provides high-performance, thread-safe data structures to replace traditional synchronized collections.
The main classes are ConcurrentMap, ConcurrentNavigableMap, ConcurrentHashMap, ConcurrentSkipListMap, ConcurrentSkipListSet, CopyOnWriteArrayList, CopyOnWriteArraySet, ConcurrentLinkedQueue, and ConcurrentLinkedDeque.
6. Synchronization Utilities
Synchronization utilities are used to implement thread synchronization and cooperation, providing functions such as counters, semaphores, and barriers.
The main classes are CountDownLatch, Semaphore, CyclicBarrier, Phaser, and Exchanger.
7. Fork/Join Framework
The fork/join framework is an important component of Java concurrency programming, used to solve divide-and-conquer problems. By decomposing a large task into several small tasks and merging the results of small tasks, we can better utilize the computing power of multi-core processors.
The main classes are ForkJoinPool, ForkJoinTask, RecursiveAction, RecursiveTask, CountedCompleter, and ForkJoinWorkerThread.
8. Reactive Streams
Reactive Streams is a reactive programming model in Java concurrent programming that provides a standard set of interfaces for implementing asynchronous data stream processing.
The main classes are Flow and SubmissionPublisher.
9. Atomic Variables
Atomic variables provide a set of thread-safe atomic operations for implementing lock-free data structures. Through atomic variables, we can achieve high-performance counters, accumulators, and other functions in a multi-threaded environment.
The main classes are AtomicInteger, AtomicLong, AtomicBoolean, AtomicIntegerArray, AtomicLongArray, AtomicReference, AtomicReferenceArray, AtomicIntegerFieldUpdater, AtomicLongFieldUpdater, AtomicReferenceFieldUpdater, AtomicMarkableReference, AtomicStampedReference, LongAdder, DoubleAdder, LongAccumulator, DoubleAccumulator, and Striped64.
10. Locks and Synchronizers
Locks and synchronizers provide mutual exclusion and coordination mechanisms between threads for synchronized access to resources. The locks and synchronizers in Java concurrent programming include reentrant locks, read-write locks, optimistic locks, and more.
The main classes are Lock, ReadWriteLock, ReentrantLock, ReentrantReadWriteLock, StampedLock, Condition, AbstractQueuedSynchronizer, AbstractQueuedLongSynchronizer, AbstractOwnableSynchronizer, and LockSupport.
11. Time Units and Exception Classes
Time units and exception classes provide some auxiliary functions such as time unit conversion, task timeouts, task cancellations, and more.
The main classes are TimeUnit, TimeoutException, CancellationException, BrokenBarrierException, ExecutionException, CompletionException, RejectedExecutionException, RejectedExecutionHandler, and Delayed.
12. Other Utility Classes
Other utility classes include some auxiliary classes for supporting concurrent programming, such as thread-local random number generators, scheduled tasks, and more.
The main classes are ThreadLocalRandom, RunnableScheduledFuture, ScheduledFuture, and Helpers.
Through the above analysis, we can better understand the components and functions of the Java concurrency framework. These classes and interfaces provide rich tools to help us more easily handle concurrency issues in actual programming. By learning these classes, we can establish a complete Java concurrency programming knowledge system, thereby improving our ability to handle concurrency issues in practical projects.
In practical applications, we should choose suitable concurrency tools according to specific scenarios, such as using the executor framework for task scheduling, using blocking queues to implement producer-consumer patterns, using atomic variables to implement lock-free data structures, etc. At the same time, we also need to pay attention to some basic principles in concurrent programming, such as avoiding deadlocks, reducing the granularity of locks, and using threads reasonably.
In summary, the Java concurrency framework provides rich tools and functions to help us better understand and master Java concurrent programming. By systematically learning and organizing this knowledge, we can more effectively solve concurrency problems in practical projects and improve our programming skills. I hope this blog can help everyone better understand the Java concurrency framework and provide guidance for us to solve concurrency problems in practical projects.
Next, I will analyze the execution principles of the above classes from the perspective of source code to help everyone understand the internal mechanism of the Java concurrency framework more deeply. Through source code-level analysis, we can understand the design ideas and implementation details of these classes, thereby better utilizing these tools to solve practical problems.