Web Services can't inherit a JDK8 default method ------------------------------------------------ Key: JBWS-3873 URL: https://issues.jboss.org/browse/JBWS-3873 Project: JBoss Web Services Issue Type: Bug Components: jbossws-cxf, jbossws-integration Affects Versions: jbossws-cxf-4.3.2, jbossws-cxf-5.0.0.Beta3 Environment: JDK8 Reporter: Jan Blizňák Attachments: jdk8-ws-defaultmethod.zip Having simple SEI and POJO webservice with JDK8 feature - default method for interface: {code} @WebService public interface GreeterSEI { default public String sayHello() { return "Hello, Default"; } } //---------------------------------------------------------- @WebService public class GreeterImpl implements GreeterSEI {} {code} When you try to execute sayHello method: {code} Service greeterService = Service.create(...); GreeterSEI g = greeterService.getPort(GreeterSEI.class); Assert.assertEquals("JBoss", greeter.sayHello()); {code} You will get a message-less IllegalStateException on server. Expected results: no exception, default implementation of method is invoked. Or if this is considered unsupported usage, the exception should be more descriptive (ie.: "Method xx not found on implementation class")