Enum in private inner class.

[Garrett Smith]

Why do I get a compiler error by putting enum SortKey inside the inner class?

class RowValidator {
    private class Row {
        final String _title;
        final Calendar _date;
        final SortKey _sortKey;
        final boolean _isSortAscending;
        public Row(String title, Calendar date, SortKey sortKey, boolean isSortAscending) 
        {
            _title = title;
            _date = date;
            _sortKey = sortKey;
            _isSortAscending = isSortAscending;
        }
        
        enum SortKey { DATE, TITLE; }
    }
}

Error:The member enum SortKey must be defined inside a static member type

[Keith Lynn]

enums are implicitly static

[Ken Blair]

...and inner classes cannot have static members. Logical consequence is that inner classes cannot declare enums.