JWI Wordnet check if word is noun

Question

Im using MITs JWI and need to check if a given word is a noun.

Currently Im trying to do it like this

IWordID wId = stemmer.getDictionary().getIndexWord(words[i], POS.NOUN).getWordIDs().get(0);
IWord localWord = stemmer.getDictionary().getWord(wId); 
if (localWord.getSynset().getType() != 1){ //This is no noun} 

The String from word[id] was stemmed this way:

List<String> lemmas = stemmer.findStems(words[i], POS.NOUN);
words[i] = lemmas.get(0); //real code checks that lemmas isnt empty

But i end up with words like

are, is, be, have ...

How can i achieve a working noun check?