ReplaySubject replays events/items to current and late Observers.

Class Declaration

Following is the declaration for io.reactivex.subjects.ReplaySubject<T> class −

public final class ReplaySubject<T>
extends Subject<T>

ReplaySubject Example

Create the following Java program using any editor of your choice in, say, C:> RxJava.

ObservableTester.java

import io.reactivex.subjects.ReplaySubject;
public class ObservableTester  {
   public static void main(String[] args) {   
      final StringBuilder result1 = new StringBuilder();
      final StringBuilder result2 = new StringBuilder();         

      ReplaySubject<String> subject = ReplaySubject.create(); 
      subject.subscribe(value -> result1.append(value) ); 
      subject.onNext("a"); 
      subject.onNext("b"); 
      subject.onNext("c"); 
      subject.subscribe(value -> result2.append(value)); 
      subject.onNext("d"); 
      subject.onComplete();

      //Output will be abcd
      System.out.println(result1);
      //Output will be abcd being ReplaySubject
      //as ReplaySubject emits all the items
      System.out.println(result2);
   }
}

Verify the Result

Compile the class using javac compiler as follows −

C:RxJava>javac ObservableTester.java

Now run the ObservableTester as follows −

C:RxJava>java ObservableTester

It should produce the following output −

abcd
abcd