1.获得多线程的方法有几种？

传统 的是继承 thread 类和实现 runnable 接口， java5 以后又有实现 callable 接口 和 java 的线程池 获得

2.与 Runnable 对比 

import java.util.concurrent.Callable;

//创建类MyThread实现Runnable接口
public class MyThread implements Runnable {
    @Override
    public void run() {

    }
}

//创建类MyThread2实现Callable接口
class MyThread2 implements Callable<Integer> {

    @Override
    public Integer call() throws Exception {
        return null;
    }
}

问题:callable 接口与 runnable 接口的区别？

答：（1）是否有返回值 （2）是否抛异常 （3）落地方法不一样，一个是 run ，一个是 call

程序代码

 

import java.util.concurrent.Callable;

//创建类MyThread实现Runnable接口
public class MyThread implements Callable<Integer> {

    @Override
    public Integer call() throws Exception {
        Thread.sleep(4000);
        System.out.println(Thread.currentThread().getName() + "  ******come in call");
        return 200;
    }
}

import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

public class CallableDemo {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        FutureTask<Integer> ft = new FutureTask<Integer>(new MyThread());
        new Thread(ft, "AA").start();
        System.out.println(Thread.currentThread().getName() + "----main");
        Integer result = ft.get();
        System.out.println("**********result: "+result);
    }
}