Java5以后，出现有返回值的多线程。

实现方式：实现Callable接口，无返回值的实现Runnable接口。

import java.util.concurrent.Callable;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;public class Test {	public static void main(String[] args) throws Exception {		ExecutorService pool = Executors.newFixedThreadPool(2);		MyCallable c1 = new MyCallable("A");		MyCallable c2 = new MyCallable("B");		Future