import io.reactivex.Observable;
import io.reactivex.observables.GroupedObservable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class TypeTest {
    public static void main(String[] args) throws Exception {
    CountDownLatch latch = new CountDownLatch(1);
    Observable<Long> source Observable.interval(1,TimeUnit.MILLISECONDS).take(20);
    Observable<GroupedObservable<String,Long>> sgb =
             source.groupBy(x->    (x%2==0)?"Even":"Odd");
    // I'd like to introduce a variable for source.reduce but I get a type error.
    // Observable<Long> sreduce = source.reduce(new Long(0),(x,y)->(x+y));
    source.reduce(new Long(0),(x,y)->(x+y)).subscribe(
            x->{System.out.println(x);latch.countDown();}
    );
    latch.await();
    }
}