Lambda: Callable variable initiated with a Runnable instance

Just found a strange and interesting Lambda behavior.

Let's have the following class:

private class Task implements Runnable {
    @Override
    public void run() {
       // something to process
    }
}

The following statement is compiling and running:

Callable task = Task::new;

Could somebody explain why this is possible ?

EDIT:

Based on answers below, check the following statements:

1.

ExecutorService executor = Executors.newSingleThreadExecutor(); executor.submit(Task::new);

2.

ExecutorService executor = Executors.newSingleThreadExecutor(); executor.submit(new Task());

On the first glance, seems the same, but actually does a totally different thing.

What happens here is exactly the above situation.

The reason is that ExecutorService has two methods:

submit(Runnable); submit(Callable);

So, using the code from 1. the executor will process the following on it's internal thread:

new Task()

The version from 2. will actually call the submit(Runnable) method and the code from Task.run will be executed.

Conclusion: just be careful with Lambdas :)