[15:46:10] johnny:/Volumes/data/projects/java/jdk/jdk9/client/deploy $ grep -R 'new WebServer(' test
test/common/com/sun/deploy/cache/CacheHandlerTest.java: server = new WebServer(port);
test/common/com/sun/deploy/cache/DeployCacheHandlerTest.java: server = new WebServer(port, handler);
test/common/com/sun/deploy/net/CrossDomainXMLTest.java: server = new WebServer(8123); //Just picked a port someone else used, no idea why
test/common/com/sun/deploy/net/CrossDomainXMLTest.java: server = new WebServer(8123); //Pick some obscure port to avoid conflict with hudson server
test/common/com/sun/deploy/net/CrossDomainXMLTest.java: server = new WebServer(8124);
test/common/com/sun/deploy/net/CrossDomainXMLTest.java: server = new WebServer(1024);
test/common/com/sun/deploy/net/DownloadEngineNoCacheTest.java: server = new WebServer(port, handler);
test/common/com/sun/deploy/net/HttpDownloadHelperTest.java: server = new WebServer(port);
test/common/com/sun/deploy/security/X509DeployKMGetHostTest.java: server = new WebServer(PORT);
test/common/com/sun/deploy/uitoolkit/impl/awt/ui/DownloadWindowForServiceTest.java: server = new WebServer(8123);
test/javaws/com/sun/javaws/jnl/BuildDescriptorDeletedTest.java: server = new WebServer(8123);
test/javaws/com/sun/javaws/PreloaderTest.java: server = new WebServer(8234);
test/platform/windows/com/sun/deploy/association/utility/WinRegistryWrapperTest.java: server = new WebServer(9123);
test/plugin/sun/plugin2/applet/AWTAppletLifecycleTest.java: server = new WebServer(8234);
test/plugin/sun/plugin2/applet/SerialAppletTest.java: server = new WebServer(12345);
test/shared/sun/tests/helpers/WebServer.java: WebServer server = new WebServer(port, handler);
[15:46:23] johnny:/Volumes/data/projects/java/jdk/jdk9/client/deploy $

This is a followup JDK bug related to https://bugs.openjdk.java.net/browse/JDK-8035895.