public class ThreadHomework { public static void main(String[] args) { T1 t1 = new T1(); T2 t2 = new T2(t1); Thread th1 = new Thread(t1); Thread th2 = new Thread(t2); th1.start(); th2.start(); } } class T1 implements Runnable { @Override public void run() { for (int i = 1; i <= 10; i++) { synchronized (this) { System.out.println("hello,world " + i); notify(); try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } } synchronized (this) { notify(); } } } class T2 implements Runnable { private T1 t1; public T2(T1 t1) { this.t1 = t1; } @Override public void run() { for (int i = 1; i <= 5; i++) { synchronized (t1) { try { t1.wait(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("hi " + i); t1.notify(); } } } } 编译错误. java:5:错误：类T2中的构造函数T2不能应用于给定的类型； T2 T2=新的T2（）； ^ 要求：T1 找到：没有参数 原因：实际论证列表和形式论证列表的长度不同 1个错误， 进一步修改代码

根据错误提示，我们需要在创建 T2 对象时传入一个 T1 类型的参数。因此，需要修改下面这行代码：

T2 t2 = new T2(t1);

这里已经正确地传入了 T1 类型的参数 t1，所以不需要再创建一个新的 T1 对象。因此，可以将下面这行代码删除：

T1 t1 = new T1();

最终的代码如下所示：

public class ThreadHomework {
    public static void main(String[] args) {
        T1 t1 = new T1();
        T2 t2 = new T2(t1);
        Thread th1 = new Thread(t1);
        Thread th2 = new Thread(t2);
        th1.start();
        th2.start();
    }
}

class T1 implements Runnable {
    @Override
    public void run() {
        for (int i = 1; i <= 10; i++) {
            synchronized (this) {
                System.out.println("hello,world " + i);
                notify();
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
        synchronized (this) {
            notify();
        }
    }
}

class T2 implements Runnable {
    private T1 t1;

    public T2(T1 t1) {
        this.t1 = t1;
    }

    @Override
    public void run() {
        for (int i = 1; i <= 5; i++) {
            synchronized (t1) {
                try {
                    t1.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("hi " + i);
                t1.notify();
            }
        }
    }
}