I think Hollandic (Hollands) is a semi-accepted demonym for Holland. Dutch (Nederlands) is the demonym for the Netherlands (Nederland), though very sporidically the word 'Netherlandic' is also used. I've seen it used exactly two times in my entire life.
People will sometimes tell you 'Dutch' can mean both something from Holland and something from the Netherlands. They're wrong. It's like saying 'Virginian' can mean both something Virginia and the USA.