concurrent包里面有很多Lock的具体实现,其具体的实现都是基于AQS实现的 ReentrantLock ReentrantLock是可重入的互斥锁,重点是重入和互斥,ReentrantLock 将由最近成功获得锁的线程所持有,当这个线程再次尝试拥有这个Lock时就是重入。互斥就是 在某一时间只有一个线程能持有Lock。 public void lock() { sync.lock(); } ...
Lock和synchronize都是默认使用非公平锁的。如果不是必要的情况下,不要使用公平锁。公平锁会来带一些性能的消耗的。 4、AQS# AQS是什么: java.util.concurrnt包中lock包下有一个抽象类:AbstractQueuedSynchronizer简称为AQS。 为实现阻塞锁和相关同步器提供一个框架,他是依赖于先进先出的等待队列。 依靠单个原子int...
execute()是 java.util.concurrent.Executor接口中唯一的方法,JDK注释中的描述是“在未来的某一时刻执行命令command”,即向线程池中提交任务,在未来某个时刻执行,提交的任务必须实现Runnable接口,该提交方式不能获取返回值。下面是对execute()方法内部原理的分析,分析前先简单介绍线程池有哪些状态,在一系列执行过程中涉...
* This class will never be serialized, but we provide a * serialVersionUID to suppress a javac warning. */// 版本号privatestaticfinal long serialVersionUID=6138294804551838833L;/** Thread this worker is running in. Null if factory fails. */// worker 所对应的线程final Thread thread;/** I...
为Java线程池默认的阻塞策略,不执行此任务,而且直接抛出一个运行时异常,切记ThreadPool[Executor].execute需要try catch,否则程序会直接退出。DiscardPolicy 直接抛弃,任务不执行,空方法 DiscardOldestPolicy 从队列里面抛弃head的一个任务,并再次execute 此task。CallerRunsPolicy...
In this tutorial, we’ll look into two such problems, deadlock and livelock, with the help of Java examples. 2. Deadlock 2.1. What Is Deadlock? A deadlock occurs when two or more threads wait forever for a lock or resource held by another of the threads. Consequently, an application ...
> Thisisthe same state asblocked, but the lockinquestionisa thin lock. |waiting| > This thread calledObject.wait()onanobject. The thread will remain thereuntilsome otherthread sends a notificationtothatobject. |sleeping| > This thread calledjava.lang.Thread.sleep(). ...
Causes this thread to begin execution; the Java Virtual Machine calls therunmethod of this thread. voidstop() Deprecated. This method is inherently unsafe. voidsuspend() Deprecated. This method has been deprecated, as it is inherently deadlock-prone. ...
* Thread state for a runnable thread. A thread in the runnable * state is executing in the Java virtual machine but it may * be waiting for other resources from the operating system * such as processor. */ RUNNABLE, /** * Thread state for a thread blocked waiting for a monitor lock....
(私有)java.util.concurrent.locks.LockSupport.setBlocker设置 //使用java.util.concurrent.locks.LockSupport.getBlocker访问 volatile Object parkBlocker; //Interruptible接口中定义了interrupt方法,用来中断指定的线程 private volatile Interruptible blocker; //当前线程的内部锁 private final Object blockerLock = new ...