package threads;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class text implements Runnable {
static Lock lock = new ReentrantLock();
public static void main(String[] args) throws InterruptedException {
testts();
new Th
我将hazelcast从2.4升级到3.3,但是发生了这个异常。
13:12:51,269 [Thread-21]: ERROR xx.xx.xxThread:1783 - run:
java.lang.IllegalMonitorStateException: Current thread is not owner of the lock! -> <not-locked>
at com.hazelcast.concurrent.lock.operations.UnlockOperation.ensureUnlocked(UnlockOperation.java:71
我知道线程可以获得自己拥有的监视器--在Java中,同步锁是reentrant,如下面的示例所示。
我的查询是,如果我使用java.util.concurrent.locks.ReentrantLock API,它将产生相同的结果,我们是否可以在同步中使用死锁,但在java.util.concurrent.locks.ReentrantLock中却永远不会。
例如:
final Object[] objects = new Object[10]
public synchronized Object setAndReturnPrevious(int index, Object va
我对java中的多线程很陌生。我试着使用locks.Here是我的代码示例。
package com;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class UsingLocks {
Lock lock = new ReentrantLock();
public static void main(String[] ar
我在Windows上的IntellijIDEA社区中运行这段代码 import static java.lang.Thread.sleep;
public class Main {
public static void main(String[] args) {
StampedLock lock = new StampedLock();
Thread th = new Thread(() -> {
long stamp = lock.tryOptimisticRead();
try {
我有一个进程,它将锁定文本文件,并在任意时间间隔内使用一个新的文本字符串对同一个文件进行写入。我还编写了另一个进程,一个WatchService,它侦听同一个目录中的更改,然后锁定文件并读取文件的内容。我认为在这里锁定文件很重要,因为我希望确保只有一个进程可以同时读写同一文件。
该代码仅成功运行以锁定文件并将内容写入文件,WatchService能够检测到目录中的更改,但无法锁定和读取内容。
根据日志,它说The process cannot access the file because another process has locked a portion of the file --但
阅读有关java.util.concurrent.locks.Condition接口的Java8文档,将给出以下示例:
class BoundedBuffer {
final Lock lock = new ReentrantLock();
final Condition notFull = lock.newCondition();
final Condition notEmpty = lock.newCondition();
final Object[] items = new Object[100];
int putptr, takeptr, coun
锁定时是否可以对锁(java.util.concurrent.locks.Lock)进行垃圾回收?假设一个纯理论的例子:
WeakReference r;
public void foo(){
Lock lock = new ReentrantLock();
r = new WeakReference(lock);
lock.lock();
}
在foo()被执行之后,lock会被垃圾回收吗?换句话说,lock.lock()是否创建了对锁的强引用?怎么又知道了?
在处理异常时,在Java文档中降级ReentrantReadWriteLock的示例看起来非常不安全。我试着写一个简单的类来简化它。你看到有什么可能失败的案例吗?
我从并发的角度寻找一个回顾,比如如果在降级之前在嵌套锁中抛出异常,这段代码可能会失败。
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
public class RWLockWrapper implements AutoCloseable {
private final ReadWriteLoc
当我在Oracle服务器上运行大量的liquibase脚本时,我得到了这个问题。SomeComputer就是我。
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
Liquibase Update Failed: C
有时,我在一些Java代码中发现,他们使用嵌套锁来实现同步方法。代码如下
// lock for appending state management
final Lock appendLock = new ReentrantLock();
// global lock for array read and write management
final ReadWriteLock arrayReadWritelock = new ReentrantReadWriteLock();
final Lock arrayReadLock = arrayReadWritelock.readLock();
ReentrantLock使用什么样的机制?我正在努力弄清楚它在Java飞行记录下会出现在哪里。我的期望是锁将在Java等待部分下,但情况似乎并非如此。
背景:
我试图通过捕获java飞行记录来调试有问题的ReentrantLock。锁本身非常简单:
public class SomeClass {
private final ReentrantLock lock = new ReentrantLock();
public void capture() {
boolean exclusive = someFunction();
try {
if (ex
//I have this main class
package IntroductionLocks;
public class Intro {
public static void main(String[] args) {
NoLockATM noLockATM = new NoLockATM();
LockedATM lockedATM = new LockedATM();
MyClass thread1 = new MyClass(noLockATM, lockedATM)
我正在做一些实践作业,并尝试使用一些虚拟代码,以便更好地理解线程和锁的概念。下面是一段(有时)陷入死锁的代码。
A.java
public class A {
private B b;
public void setB(B b) {
this.b = b;
}
public synchronized void foo(boolean callBar) {
System.out.println("foo");
if (callBar) {
b.bar(false);
我对断言lock.getHoldCount() == 0的方法感到困惑;下面的示例来自Java,它写的是Returns: the number of holds on this lock by the current thread, or zero if this lock is not held by the current thread,我不太理解。
class X {
ReentrantLock lock = new ReentrantLock();
// ...
public void m() {
assert lock.getHoldCo
我需要在不同的线程中使用ReentrantLock。这有可能吗?附注:在secondMethod "lock.unlock()“抛出IllegalMonitorStateException。
public class SomeClass {
private static ConcurrentHashMap<String, String> hashMap = new ConcurrentHashMap<>();
private final Lock lock = new ReentrantLock();
public void first
我有一个Spring引导应用程序,其中有用于缓存的Hazelcast。当使用Hazelcast群集多个实例时,我在解锁操作上有此异常:
java.lang.IllegalMonitorStateException: Current thread is not owner of the lock! -> Owner: 33ce48f8-dda3-471f-abae-994d25dcc030, thread ID: 55
at com.hazelcast.concurrent.lock.operations.UnlockOperation.unlock(UnlockOperation
我正在寻找一种解决方案,允许多个线程读取共享资源(允许并发性),但一旦线程进入变异块,就会锁定这些读取线程,以实现这两个世界的最佳效果。
class Foo {
Map<String, String> sharedResource;
public void read() // multiple reading threads allowed, concurrency ok, lock this only if a thread enters the mutating block below.
{
// read concurrently