@SuppressWarnings("unchecked")
    static <T> T maskNull(T key)
    {
        return (key == null ? (T)NULL_KEY : key);
    }
@SuppressWarnings("unchecked")
    static <T> T maskNull(T key)
    {
        return (key == null ? (T)NULL_KEY : key);
    }
@ SuppressWarnings ( "unchecked" ) static < T > T maskNull ( T key ) { return ( key == null ? ( T ) NULL_KEY : key ) ; }
Returns internal representation for key. Use NULL_KEY if key is null.
Returns internal representation for key . Use NULL_KEY if key is null .