AsyncTest.java

import static io.vertx.core.Vertx.vertx;
import io.vertx.core.AsyncResult;
import io.vertx.core.Handler;

import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

public class AsyncTest {

	@Test
	public void testProducts() {
		// Create some products
		List<Product> products = new ArrayList<>();
		for (int i = 0; i < 10; i++) {
			products.add(new Product("Test_" + i));
		}

		// Iterate over the products and transform them asynchronously
		List<String> transformed = new ArrayList<>();
		for (Product product : products) {
			product.transform(rh -> {
				transformed.add(rh.result());
			});
		}

		// Check the transformed list.
		System.out.println(transformed.size());
	}
}

class Product {

	String name;

	public Product(String name) {
		this.name = name;
	}

	Product transform(Handler<AsyncResult<String>> handler) {
		vertx().executeBlocking(bc -> {
			try {
				Thread.sleep(100);
			} catch (Exception e) {
			}
			bc.complete(name);
		}, handler);
		return this;
	}

}