gistfile1.java

```
import rx.Observable;

import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

public class TestRxJava {

    public static void main(String[] args) {

        Observable<Integer> obs1 = Observable.<Integer>create(aSubscriber -> {


            AtomicInteger i = new AtomicInteger(0);
            Executors.newScheduledThreadPool(10).scheduleAtFixedRate(() -> {
                aSubscriber.onNext(i.get());
                if (i.incrementAndGet() == 10) {
                    System.out.println("One Finished sending");
                    aSubscriber.onCompleted();
                }
            }, 500, 500, TimeUnit.MILLISECONDS);

            System.out.println("One subscribed to");
            return null;
        });


        Observable<Integer> obs2 = Observable.<Integer>create(aSubscriber -> {
            System.out.println("Two subscribed to");
            for (int i = 1; i < 10; i++) {
                aSubscriber.onNext(i);
            }
            System.out.println("Two Finished sending");
            aSubscriber.onCompleted();
            System.out.println("Two Finished complete");
            return null;
        });

        Observable.concat(obs1, obs2).subscribe(num -> {
            System.out.println("Received: " + num);
        });


        System.out.println("Main done");

    }
}
```

```
One subscribed to
Main done
Received: 0
Received: 1
Received: 2
Received: 3
Received: 4
Received: 5
Received: 6
Received: 7
Received: 8
Received: 9
One Finished sending
Two subscribed to
Received: 1
Received: 2
Received: 3
Received: 4
Received: 5
Received: 6
Received: 7
Received: 8
Received: 9
Two Finished sending
Two Finished complete
```