CompletableFuture test with time benchmark

CompatableFutureTest

import org.apache.commons.lang3.time.StopWatch;
import org.junit.Assert;
import org.junit.Test;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class CompatableFutureTest {

    @Test
    public void test() {
        StopWatch watch = new StopWatch();
        watch.start();

        CompletableFuture<String> future1
                = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "Hello";
        });
        CompletableFuture<String> future2
                = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "Beautiful";
        });
        CompletableFuture<String> future3
                = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "World";
        });

        CompletableFuture<String> future4
                = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "Yay!";
        });

        String combined = Stream.of(future1, future2, future3, future4)
                .map(CompletableFuture::join)
                .collect(Collectors.joining(" "));

        Assert.assertEquals("Hello Beautiful World Yay!", combined);
        watch.stop();
        System.out.println("Time Elapsed: " + watch.getTime());
    }

}