ThenCombineExample.java

package com.java.latest;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

public class Sample {

	public static void main(String[] args) throws InterruptedException, ExecutionException {
			ExecutorService executor = Executors.newScheduledThreadPool(2, new MyThreadFactory());

			CompletableFuture<Integer> cf = CompletableFuture.supplyAsync(() -> {
				return 1;
			}, executor);

			CompletableFuture<Integer> cf1 = CompletableFuture.supplyAsync(() -> {
				return 2;
			}, executor);
			
			CompletableFuture<Integer> result = cf.thenCombine(cf1, (x,y) -> {
				return add(x,y);
			});

			System.out.println("Result " + result.get());

			// shutdown executor manually
			executor.shutdown();
		}

		public static int add(int x, int y) {
			return x + y;
		}
}

class MyThreadFactory implements ThreadFactory {
	static int i = 1;

	public Thread newThread(Runnable r) {
		Thread t = new Thread(r, "" + i);
		i++;
		return t;
	}
}