CompletableFuture gotcha

FutureWUT.java

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class FutureWUT {

    static void sleep(long millis) {
        try {
            Thread.sleep(millis);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws InterruptedException {
        CompletableFuture<Object> firstProcess = CompletableFuture.supplyAsync(() -> {
            sleep(2000L);
            System.out.println("first process");
            return "1";
        });

        CompletableFuture<Object> secondProcess = firstProcess.thenApplyAsync(v -> {
            sleep(3000);
            System.out.println("second process");
            return "2";
        });


        CompletableFuture<Void> completableFuture = CompletableFuture.allOf(firstProcess, secondProcess);
        completableFuture.thenApplyAsync(v -> {
            System.out.println("allOf completed");
            return "3";
        });
        try {
            completableFuture.get(100, TimeUnit.MILLISECONDS);
        } catch (Exception e) {
            System.out.println("Timeout!");
        }

        Thread.sleep(10000);
    }
}