Ext6 ext = ExtensionLoader.getExtensionLoader(Ext6.class).getAdaptiveExtension();
URL url = new URL("p1", "1.2.3.4", 1010, "path1");
url = url.addParameters("ext6", "impl1");
assertEquals("Ext6Impl1-echo-Ext1Impl1-echo", ext.echo(url, "ha"));
Assert.assertTrue("can not find error.", LogUtil.checkNoError());
LogUtil.stop();
url = url.addParameters("simple.ext", "impl2");