public class Test1 extends Thread{ static int data[]=new int[5]; static Semaphore s1=new Semaphore(1); static void put(int num) { try { s1.acquire(); for(int i=0;i<5;i++) { data[i]=num; } s1.release(); } catch (InterruptedException e) { throw new RuntimeException(e); } } public void run() { put(2); put(5); put(0); } public static void main(String[] args) { Thread t1=new Thread(()->Test1.put(2)); Thread t2=new Thread(()->Test1.put(5)); Thread t3=new Thread(()->Test1.put(0)); t1.start(); t2.start(); t3.start(); try { t1.join(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { t2.join(); } catch (InterruptedException e) { throw new RuntimeException(e); } try { t3.join(); } catch (InterruptedException e) { throw new RuntimeException(e); } try { s1.acquire(); for(int j=0;j<5;j++) { System.out.println(data[j]); } s1.release(); } catch (InterruptedException e) { throw new RuntimeException(e); } } }将这段代码修改为输出结果总是5

要让输出结果总是5，可以将put()方法中的for循环改为只给数组的第一个元素赋值为num。此外，需要将Semaphore的许可证数量改为5，确保只有当所有数据都被写入数组后，才能进行输出操作。修改后的代码如下：

public class Test1 extends Thread {
    static int data[] = new int[5];
    static Semaphore s1 = new Semaphore(5);

    static void put(int num) {
        try {
            s1.acquire();
            data[0] = num;
            s1.release();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }

    public void run() {
        put(2);
        put(5);
        put(0);
    }

    public static void main(String[] args) {
        Thread t1 = new Thread(() -> Test1.put(2));
        Thread t2 = new Thread(() -> Test1.put(5));
        Thread t3 = new Thread(() -> Test1.put(0));
        t1.start();
        t2.start();
        t3.start();
        try {
            t1.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        try {
            t2.join();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        try {
            t3.join();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        try {
            s1.acquire(5);
            for (int j = 0; j < 5; j++) {
                System.out.println(data[j]);
            }
            s1.release(5);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
}

输出结果将总是5。