方法体执行完，线程会释放吗？

public class Application {    public static void main(String[] args) throws Exception {        //SpringApplication.run(Application.class, args);    Application application = new Application();        for(int i=0; i<10000; i++){    Application.Sub sub = application.new Sub();        boolean value = sub.test();    System.out.println("end="+value);    }    }    class Sub{    public Boolean test() throws Exception{    ExecutorService service = Executors.newFixedThreadPool(2);    CompletionService<Boolean> completionService = new ExecutorCompletionService<Boolean>(service);        try {    for(int i=0; i<1; i++){        completionService.submit(new Callable<Boolean>() {    @Override    public Boolean call() throws Exception {    Thread.sleep(100);    //throw new NullPointerException("lalalalala");    return true;    }    });        }                for(int i=0; i<1; i++){        System.out.println(completionService.take().get());        }} catch (Exception e) {System.out.println(e.getMessage());return false;} finally {service.shutdown();}        return true;    }    }    }