java.lang.NoSuchMethodError when invoking java.lang.Object methods on proxies created by `ConfigProxyFactory`

[jjteo74]

public interface AppSettings {
  String getHost();
}

AppSettings settings = configProxyFactory.newProxy(AppSettings.class);

settings.getHost(); // ok
settings.toString(); // ok
settings.hashCode(); // NoSuchMethodError
settings.equals(settings); // NoSuchMethodError