Suggest adding "private static Function..." to java constants examples

The Java style guide says that `private static final` variables where the value is immutable, are constants and should be in UPPER_CASE.

Read literally, this means that a function would be no exception:

private static final Function REMOVE_NUMBERS = s -> s.replaceAll("\\d","");

If this is the suggested style, I suggest adding it to the examples. The sentence below about most of these being nouns, probably doesn't apply in this case?