多线程之创建线程有哪几种方式？

这个问题一般会出现在面试当中，多线程创建有哪几种方式呢？
答：实现Runable接口和实现Thread类。

我们先看看看实现这两种的实现方式

package com.summer;

public class ThreadA implements Runnable {

    public void run() {
        System.out.println("start ThreadA!");
    }

    public static void main(String[] args) {
        Thread thread = new Thread(new ThreadA());
        thread.start();
    }
}

package com.summer;

public class ThreadB extends Thread {

    @Override
    public void run() {
        System.out.println("start ThreadB!");
    }

    public static void main(String[] args) {
        ThreadB threadB = new ThreadB();
        threadB.start();
    }
}

那么除了这两种方式以外还有什么其他方式呢？

答：可以实现Callable接口和线程池来创建线程。

package com.summer;

import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;

public class ThreadC implements Callable {

    public Object call() throws Exception {
        System.out.println("start ThreadC!");
        return null;
    }

    public static void main(String[] args) {
        ThreadC threadC = new ThreadC();
        FutureTask futureTask = new FutureTask(threadC);
        Thread thread = new Thread(futureTask);
        thread.start();
    }
}

package com.summer;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ThreadD implements Runnable {

    public void run() {
        System.out.println("start ThreadD!");
    }

    public static void main(String[] args) {
        ExecutorService executorService = Executors.newSingleThreadExecutor();
        executorService.execute(new ThreadD());
    }
}