FutureTask<String> task = new FutureTask(new Callable{
       public void call(){
             //TODO
       }
 });
Thead thread = new Thread(task);
thread.start();

/**
 * 返回 Callable 对象，调用它时可运行给定的任务并返回 null
 */  
static Callable<Object> callable(Runnable task)   
/**
 * 返回 Callable 对象，调用它时可运行给定的任务并返回给定的结果
 */  
static <T> Callable<T> callable(Runnable task, T result)   

 public static <T> Callable<T> callable(Runnable task, T result) {  
    if (task == null)  
        throw new NullPointerException();  
    return new RunnableAdapter<T>(task, result);  
}  

/**
 * A callable that runs given task and returns given result
 */
static final class RunnableAdapter<T> implements Callable<T> {
    final Runnable task;
    final T result;
    RunnableAdapter(Runnable task, T result) {
        this.task = task;
        this.result = result;
    }
    public T call() {
        task.run();
        return result;
    }
}

/**
 * A task that returns a result and may throw an exception.
 * Implementors define a single method with no arguments called
 * {@code call}.
 *
 * <p>The {@code Callable} interface is similar to {@link
 * java.lang.Runnable}, in that both are designed for classes whose
 * instances are potentially executed by another thread.  A
 * {@code Runnable}, however, does not return a result and cannot
 * throw a checked exception.
 *
 * <p>The {@link Executors} class contains utility methods to
 * convert from other common forms to {@code Callable} classes.
 *
 * @see Executor
 * @since 1.5
 * @author Doug Lea
 * @param <V> the result type of method {@code call}
 */
@FunctionalInterface
public interface Callable<V> {
    /**
     * Computes a result, or throws an exception if unable to do so.
     *
     * @return computed result
     * @throws Exception if unable to compute a result
     */
    V call() throws Exception;
}

<T> Future<T> submit(Callable<T> task)  

result = executorService.submit(aCallable).get();   

public class Demo {

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService executor = Executors.newCachedThreadPool();
        Future<String> future = executor.submit(new Callable<String>() {
            @Override
            public String call() throws Exception {
                System.out.println("call");
                TimeUnit.SECONDS.sleep(1);
                return "str";
            }
        });
        System.out.println(future.get());
    }
}

public <T> Future<T> submit(Callable<T> task) {
    if (task == null) throw new NullPointerException();
    RunnableFuture<T> ftask = newTaskFor(task);
    execute(ftask);
    return ftask;
}

protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
    return new FutureTask<T>(callable);
}

public void execute(Runnable command) {
        if (command == null)
            throw new NullPointerException();

        int c = ctl.get();
        if (workerCountOf(c) < corePoolSize) {
            if (addWorker(command, true))
                return;
            c = ctl.get();
        }
        if (isRunning(c) && workQueue.offer(command)) {
            int recheck = ctl.get();
            if (! isRunning(recheck) && remove(command))
                reject(command);
            else if (workerCountOf(recheck) == 0)
                addWorker(null, false);
        }
        else if (!addWorker(command, false))
            reject(command);
    }