java进程间通信问题

import java.util.ArrayList;

import java.util.List;



public class FirstThread {

	public static void main(String[] args) throws InterruptedException {

		List<Object> goods = new ArrayList<>();	//储存物品的仓库，最多储存1

		Thread thread1 = new Thread(()->{		//线程1，生产产品

			int num = 0;

			while(true) {

				synchronized (goods) {

					if(goods.size()==0) goods.add("商品" + ++num);

					else if(goods.size()>0)

						try {

							goods.wait();

						} catch (InterruptedException e) {

							// TODO Auto-generated catch block

							e.printStackTrace();

						}

					System.out.println("生产者生产了第"+num+"个产品");

					

				}

				try {

					Thread.sleep(100);

				} catch (InterruptedException e) {

					// TODO Auto-generated catch block

					e.printStackTrace();

				}

			}

		}, "生产者");

		Thread thread2 = new Thread(()->{

			int num = 0;

			while(true) {

				synchronized (goods) {

					if(goods.size()>0) goods.remove("商品"+ ++num);

					else if (goods.size()==0)

						goods.notify();

					System.out.println("消费者消费了第"+num+"个产品");

					

				}

				try {

					Thread.sleep(100);

				} catch (InterruptedException e) {

					// TODO Auto-generated catch block

					e.printStackTrace();

				}

			}

		}, "消费者");

		thread1.start();

		thread2.start();

	}

}