Java并发编程中高频异常的原因,场景与解决方案全解析

public class InterruptDemo {
    public static void main(String[] args) throws InterruptedException {
        Thread t1 = new Thread(() -> {
            try {
                // 线程休眠10秒
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                System.out.println("线程休眠被中断：" + e.getMessage());
                // 重置中断状态（关键！）
                Thread.currentThread().interrupt();
            }
        });
        t1.start();
        
        // 1秒后中断t1线程
        Thread.sleep(1000);
        t1.interrupt();
    }
}

public class IllegalMonitorDemo {
    private static final Object lock = new Object();
    
    public static void main(String[] args) {
        // 直接调用wait()，未持有lock的锁
        lock.wait(); // 抛出IllegalMonitorStateException
    }
}

public class IllegalMonitorDemo {
    private static final Object lock = new Object();
    
    public static void main(String[] args) throws InterruptedException {
        synchronized (lock) { // 必须先获取lock的监视器锁
            lock.wait(); // 正确：当前线程持有lock的锁
        }
    }
}

Lock lock = new ReentrantLock();
Condition condition = lock.newCondition();
lock.lock(); // 获取锁
try {
    condition.await(); // 替代wait()
} finally {
    lock.unlock(); // 释放锁
}

public class ConcurrentModificationDemo {
    private static final List<Integer> list = new ArrayList<>();
    
    public static void main(String[] args) {
        // 线程1：循环添加元素
        new Thread(() -> {
            for (int i = 0; i < 1000; i++) {
                list.add(i);
            }
        }).start();
        
        // 线程2：循环迭代并修改
        new Thread(() -> {
            for (Integer num : list) { // 迭代时触发检查
                list.remove(num); // 抛出ConcurrentModificationException
            }
        }).start();
    }
}

// 线程安全的ArrayList替代方案
private static final List<Integer> list = new CopyOnWriteArrayList<>();

public class RejectedExecutionDemo {
    public static void main(String[] args) {
        // 配置线程池：核心2，最大5，队列10，拒绝策略AbortPolicy
        ThreadPoolExecutor executor = new ThreadPoolExecutor(
            2, 5, 60L, TimeUnit.SECONDS,
            new ArrayBlockingQueue<>(10),
            new ThreadPoolExecutor.AbortPolicy() // 默认拒绝策略：直接抛异常
        );
        
        // 提交16个任务（最大容量5+10=15），第16个被拒绝
        for (int i = 0; i < 16; i++) {
            int finalI = i;
            executor.submit(() -> {
                try {
                    Thread.sleep(1000);
                    System.out.println("执行任务：" + finalI);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            });
        }
        executor.shutdown();
    }
}

ThreadPoolExecutor executor = new ThreadPoolExecutor(
    2, 5, 60L, TimeUnit.SECONDS,
    new ArrayBlockingQueue<>(10),
    new ThreadPoolExecutor.CallerRunsPolicy() // 提交线程执行被拒绝的任务
);