java-tutorials/spring-scheduling/src/main/java/com/baeldung/async/AsyncService.java

package com.baeldung.async;

import java.util.concurrent.CompletableFuture;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class AsyncService {

    @Autowired
    private FirstAsyncService fisrtService;
    @Autowired
    private SecondAsyncService secondService;

    public CompletableFuture<String> asyncMergeServicesResponse() throws InterruptedException {
        CompletableFuture<String> fisrtServiceResponse = fisrtService.asyncGetData();
        CompletableFuture<String> secondServiceResponse = secondService.asyncGetData();

        // Merge responses from FirstAsyncService and SecondAsyncService
        return fisrtServiceResponse.thenCompose(fisrtServiceValue -> secondServiceResponse.thenApply(secondServiceValue -> fisrtServiceValue + secondServiceValue));
    }
}