List<String> extraClasspath = Arrays.asList(cp1, cp2);
vertx.deployVerticle("java:" + TestVerticle.class.getCanonicalName(), new DeploymentOptions().setIsolationGroup("somegroup").
setExtraClasspath(extraClasspath), ar -> {
assertTrue(ar.succeeded());
Deployment deployment = ((VertxInternal) vertx).getDeployment(ar.result());
Verticle verticle = deployment.getVerticles().iterator().next();
ClassLoader cl = verticle.getClass().getClassLoader();
URLClassLoader urlc = (URLClassLoader) cl;
assertTrue(urlc.getURLs()[0].toString().endsWith(cp1));
assertTrue(urlc.getURLs()[1].toString().endsWith(cp2));
testComplete();
});