Question

I want to use an anonymous class for Runnable. There are two ways, but I don’t know if they do the same thing or not:

Method one: using Runnable directly and then calling run():

new Runnable() {
    @Override
    public void run() {
    }
}.run();

Method two: create an anonymous Runnable and paste to Thread, using the start() method instead of run():

new Thread(new Runnable() {
    @Override
    public void run() {
    }
}).start();

I think method two is obviously true. But, I don’t know if it does the same thing as method one. Can we call the run() method on a Runnable directly?

Answer 1

No, you usually won’t call run() directly on a Runnable as you will get no background threading that way. If you don’t want and need a background thread, then fine call run() directly, but otherwise if you want to create a background thread and run your Runnable from within it, you must create a new Thread and then pass in the Runnable into its constructor, and call start().

Also, there are other ways of accomplishing this task including use of Executors and ExecutorServices, and you should look into the uses of this as they offer more flexibility and power than using a bare bones Thread object.

Also you’ll want to have a look at use of the Future interface and the FutureTasks class that are like Runnables only they allow you to return a result when complete. If you’ve used a SwingWorker, then you’ve already used a Future interface without realizing it.