Calling method Sequencely

1. Execute multiple task sequencly (WAY-1)

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import io.reactivex.Observable;
import io.reactivex.ObservableEmitter;
import io.reactivex.ObservableOnSubscribe;
public class TestClass2 {

    public static void main(String[] args){

        Observable<String> myObservable = Observable.create(
                new ObservableOnSubscribe<String>() {
            @Override
            public void subscribe(ObservableEmitter<String> sub) throws Exception {
                // "Emit" any data to the subscriber
                sub.onNext(showData("a"));
                sub.onNext(showData("b"));
                sub.onNext(showData("c"));
                // Trigger the completion of the event
                sub.onComplete();
            }
        });
        myObservable.subscribe();
    }

    public static String showData(String msg){
        System.out.println(msg);

        return msg;
    }

}

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2. Execute multiple task sequencly (WAY-2)

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import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;

public class TestClass3 {

    public static void main(String[] args){

        Observer<String> mySubscriber = new Observer<String>() {
            @Override
            public void onSubscribe(Disposable disposable) {
                System.out.println("onSubscribe");
            }

            @Override
            public void onNext(String s) {
                System.out.println("onNext: " + s);
            }

            @Override
            public void onError(Throwable throwable) {
                System.out.println("Error");
            }

            @Override
            public void onComplete() {
                System.out.println("done!");
            }
        };

        mySubscriber.onNext("a");
        mySubscriber.onNext("b");
        mySubscriber.onNext("c");

        mySubscriber.onComplete();

    }
}

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