@oleg-nenashev 
I could not get what you mean. `RebuildParameterPage` can be overridden if developers need.
Or you think of usage like this?

    return new RebuildParameterPage() { // now RebuildParameterPage is defined as an interface.
        public Class<?> getClazz() {return xxxxx.class;}
        public String getPage() {return "xxxx.jelly";}
    };