import java.util.ArrayList;

import java.util.List;

public class MyList {

    private static List list = new ArrayList();

    public static void add() {

        list.add("anyString");

    }

    public static int size() {

        return list.size();

    }

}

import extlist.MyList;

public class ThreadA extends Thread {

    private Object lock;

    public ThreadA(Object lock) {

        super();

        this.lock = lock;

    }

    @Override

    public void run() {

        try {

            synchronized (lock) {

                if (MyList.size() != ) {

                    System.out.println("wait begin "

                            + System.currentTimeMillis());

                    lock.wait();

                    System.out.println("wait end  "

                            + System.currentTimeMillis());

                }

            }

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}

import extlist.MyList;

public class ThreadB extends Thread {

    private Object lock;

    public ThreadB(Object lock) {

        super();

        this.lock = lock;

    }

    @Override

    public void run() {

        try {

            synchronized (lock) {

                for (int i = ; i < ; i++) {

                    MyList.add();

                    if (MyList.size() == ) {

                        lock.notify();

                        System.out.println("已发出通知！");

                    }

                    System.out.println("添加了" + (i + ) + "个元素!");

                    Thread.sleep();

                }

            }

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}

import extthread.ThreadA;

import extthread.ThreadB;

public class Run {

    public static void main(String[] args) {

        try {

            Object lock = new Object();

            ThreadA a = new ThreadA(lock);

            a.start();

            Thread.sleep();

            ThreadB b = new ThreadB(lock);

            b.start();

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

namespace ConsoleApplication1

{

    internal class Program

    {

        private static void Main(string[] args)

        {

            var obj = new object();

            var thread1 = new Thread(Test1);

            thread1.Start(obj);

            Thread.Sleep();

            var thread2 = new Thread(Test2);

            thread2.Start(obj);

        }

        public static void Test1(object obj)

        {

            try

            {

                Monitor.Enter(obj);

                if (MyList.Size() != )

                {

                    Console.WriteLine("wait begin" + DateTime.Now);

                    Monitor.Wait(obj);

                    Console.WriteLine("wait end" + DateTime.Now);

                }

                Monitor.Exit(obj);

            }

            catch (Exception ex)

            {

                throw new Exception(ex.Message);

            }

        }

        public static void Test2(object obj)

        {

            try

            {

                Monitor.Enter(obj);

                for (int i = ; i < ; i++)

                {

                    MyList.Add();

                    if (MyList.Size() == )

                    {

                        Monitor.Pulse(obj);

                        Console.WriteLine("已发出通知！" + DateTime.Now);

                    }

                    Console.WriteLine("添加了(" + (i + ) + ")个元素");

                    Thread.Sleep();

                }

                Monitor.Exit(obj);

            }

            catch (Exception ex)

            {

                throw new Exception(ex.Message);

            }

        }

    }

    public class MyList

    {

        private static readonly List<string> list = new List<string>();

        public static void Add()

        {

            list.Add("anyString");

        }

        public static int Size()

        {

            return list.Count();

        }

    }

}