多线程面试题

题目：主线程执行10次，子线程执行10次，此过程重复50次

代码：

package com.Thread.test;
/*
 * function:主线程执行10次，子线程执行10次，
 * 此过程重复50次
 */
public class ThreadProblem {

	public ThreadProblem() {
		
		final Business bus = new Business();
		new Thread(new Runnable() {
			
			public void run() {
				
				for(int j=0;j<50;j++) {
					
					bus.sub(j);
				}
			}
		}).start();
		
		for(int j=0;j<50;j++) {
			
			bus.main(j);
		}
	}
	class Business {
		
		private boolean tag=true;
		public synchronized void sub(int num) {
			
			if(!tag) {
				
				try {
					this.wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			for(int i=0;i<10;i++)
			{
				System.out.println("sub thread "+i+",loop "+num+".");
			}
			
			tag=false;
			notify();
		}
		
		public synchronized void main(int num) {
			
			if(tag) {
				
				try {
					this.wait();
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			for(int i=0;i<10;i++) {
				
				System.out.println("main thread "+i+",loop "+num+".");
			}
			
			tag=true;
			notify();
		}
	}
	
	public static void main(String[] args) {
		
		ThreadProblem problem = new ThreadProblem();
	}
}