new Thread(task).start(); String result = task.get(); // 调用get()阻塞主线程，反之，线程不会阻塞

 callable -> task -> Thread,task插在中间，通过task获得结果，而不是Thread.

package com.skex.callable;

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

/**
 * Created on 2016/5/18.
 */
public class CallableImpl implements Callable<String> {

    public CallableImpl(String acceptStr) {
        this.acceptStr = acceptStr;
    }

    private String acceptStr;

    @Override
    public String call() throws Exception {
        // 任务阻塞 1 秒
        Thread.sleep(3000);
        return this.acceptStr + " append some chars and return it!";
    }


    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Callable<String> callable = new CallableImpl("my callable test!");
        FutureTask<String> task = new FutureTask<>(callable);
        long beginTime = System.currentTimeMillis();
        // 创建线程
        new Thread(task).start();
        // 调用get()阻塞主线程，反之，线程不会阻塞
        String result = task.get();
        long endTime = System.currentTimeMillis();
        System.out.println("hello : " + result);
        System.out.println("cast : " + (endTime - beginTime) / 1000 + " second!");
    }
}