gistfile1.txt

import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;

public class ParallelProcessingExample {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        List<Integer> list1 = List.of(1, 2, 3);
        List<Integer> list2 = List.of(4, 5, 6);
        List<Integer> list3 = List.of(7, 8, 9);

        // Process each list asynchronously and get a CompletableFuture for each
        CompletableFuture<List<String>> future1 = CompletableFuture.supplyAsync(() -> processList1(list1));
        CompletableFuture<List<String>> future2 = CompletableFuture.supplyAsync(() -> processList2(list2));
        CompletableFuture<List<String>> future3 = CompletableFuture.supplyAsync(() -> processList3(list3));

        // Combine the results using allOf and then gather the results into a list
        CompletableFuture<List<List<String>>> allFutures = CompletableFuture.allOf(future1, future2, future3)
                .thenApply(voidResult -> List.of(future1.join(), future2.join(), future3.join()));

        // Get the combined results
        List<List<String>> results = allFutures.get();

        // Flatten the results into a single list if needed
        List<String> combinedResults = results.stream()
                .flatMap(List::stream)
                .collect(Collectors.toList());

        System.out.println("Combined Results: " + combinedResults);
    }

    private static List<String> processList1(List<Integer> list) {
        return list.stream()
                .map(item -> "Processed List 1 item: " + item)
                .collect(Collectors.toList());
    }

    private static List<String> processList2(List<Integer> list) {
        return list.stream()
                .map(item -> "Processed List 2 item: " + item)
                .collect(Collectors.toList());
    }

    private static List<String> processList3(List<Integer> list) {
        return list.stream()
                .map(item -> "Processed List 3 item: " + item)
                .collect(Collectors.toList());
    }
}