java死锁和活锁

Java中的死锁和活锁是两种常见的多线程问题。死锁指的是两个或多个线程互相等待对方释放锁，导致所有线程被阻塞无法继续执行的情况。而活锁则是指多个线程一直重试某个操作，但无论如何都无法成功完成任务，导致程序无法继续正常运行。

// 死锁示例public class DeadlockExample {private final Object lock1 = new Object();private final Object lock2 = new Object();public void method1() {synchronized (lock1) {System.out.println("method1 acquired lock1");try {Thread.sleep(100);} catch (InterruptedException ignored) {}synchronized (lock2) {System.out.println("method1 acquired lock2");// do some work}}}public void method2() {synchronized (lock2) {System.out.println("method2 acquired lock2");try {Thread.sleep(100);} catch (InterruptedException ignored) {}synchronized (lock1) {System.out.println("method2 acquired lock1");// do some work}}}public static void main(String[] args) {DeadlockExample example = new DeadlockExample();new Thread(example::method1).start();new Thread(example::method2).start();}}// 活锁示例public class LivelihoodExample {private volatile boolean needSupplies = true;private final Object lock = new Object();public void goToMarket() {while (needSupplies) {System.out.println("Going to market...");try {Thread.sleep(100);} catch (InterruptedException ignored) {}}System.out.println("Finished shopping");}public void purchaseSupplies() {while (needSupplies) {synchronized (lock) {System.out.println("Trying to buy supplies...");try {Thread.sleep(100);} catch (InterruptedException ignored) {}}}System.out.println("Got the supplies");}public static void main(String[] args) {LivelihoodExample example = new LivelihoodExample();new Thread(example::goToMarket).start();new Thread(example::purchaseSupplies).start();}}

要避免死锁，可以尽量减少锁的使用，避免过度嵌套锁的情况，或者使用一些锁的分配策略来保证线程的顺序。而活锁则需要通过一定的算法设计来解决，例如引入随机因素或退避机制来降低线程之间的冲突。

上一篇：amd虚拟机用的macos系统

下一篇：php hr