RxJava - Trampoline Scheduler

Schedulers.trampoline() method creates and returns a Scheduler that queues work on the current thread to be executed after the current work completes.

Example - Usage of Schedulers.trampoline()

ObservableTester.java

package com.tutorialspoint;

import java.util.Random;

import io.reactivex.rxjava3.core.Observable;
import io.reactivex.rxjava3.schedulers.Schedulers;

public class ObservableTester  {
   public static void main(String[] args) throws InterruptedException {
      Observable.just("A", "AB", "ABC")
         .flatMap(v -> getLengthWithDelay(v)
         .doOnNext(s -> System.out.println("Processing Thread " 
            + Thread.currentThread().getName()))
         .subscribeOn(Schedulers.trampoline()))
         .subscribe(length -> System.out.println("Receiver Thread " 
            + Thread.currentThread().getName() 
            + ", Item length " + length));

         Thread.sleep(10000);
   }
   protected static Observable<Integer> getLengthWithDelay(String v) {
      Random random = new Random();
      try {
         Thread.sleep(random.nextInt(3) * 1000);
         return Observable.just(v.length());
      } catch (InterruptedException e) {
         e.printStackTrace();
      }
      return null;
   }
}

Output

Compile and Run the code to verify the following output −

Processing Thread main
Receiver Thread main, Item length 1
Processing Thread main
Receiver Thread main, Item length 2
Processing Thread main
Receiver Thread main, Item length 3