生産者消費者java実現

package sjms;

import java.util.LinkedList;
import java.util.Queue;

public class product_custom {
    public static void main(String[] args) {
        buffer b=new buffer();
        customer c=new customer(b);
        producer p=new producer(b);
        c.start();
        p.start();
    }
    // 
    static class  customer extends  Thread {
         buffer b=new buffer();
         customer(buffer b){
             this.b=b;
         }
         public void run(){
             for (int i = 0; i <10 ; i++) {
                 try {

                     int getval= b.getit();
                     System.out.println(" "+getval);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
             }
         }
    }

    // 
    static class   producer extends Thread{
        buffer b=new buffer();
        producer(buffer b){
            this.b=b;
        }
        public void run(){
            for (int i = 0; i <10 ; i++) {
                try {
                    b.add(i);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    // 
    static class buffer {
       // 
        Queue queue=new LinkedList<>();
        int maxsize=5;
        public synchronized void add(int val) throws InterruptedException {
            if(queue.size()>maxsize)  wait();
            queue.add(val);
            notify();
        }

        public  synchronized  int getit() throws InterruptedException {
            if(queue.size()==0) wait();
            int val= queue.poll();
            notify();
            return val;
        }
    }
}