If I try to create a custom message composer/context mapper that subclasses existing message composer/context mapper (for example HttpMessageComposer) then the resulting class looks like:

public class CustomMessageComposer extends HttpMessageComposer implements MessageComposer {
}

The following error is displayed: The interface MessageComposer cannot be implemented more than once with different arguments: MessageComposer<HttpBindingData> and MessageComposer

There are two possble solutions:
1. If a super class contains MessageComposer interface, then don't add the interface to the resulting class
2. Parametrize MessageComposer interface w/r/t the super class's type parameter (MessageComposer<HttpBindingData>)