Null Pointer Exception stanford core nlp pipeline (CorelLabel)

Question

I am trying to use stanford nlp pipeline for doing some basic NER and POS. I have slightly modified the core-nlp code to accomodate both ngram and training using a prop file. I feel the problem is with the way I am passing through the pipeline.

public class TestQG {

    public static void main(String[] args) throws Exception {

        String originaltext = "Obama is the President of America";
        String modifiedtext = originaltext.replaceAll("[+,:;=?@#|<>.^*()%!]", "");

        stanfordNLPParser(modifiedtext, useCustomNLPModel, customStopWordList, useCustomTokenREGEX);

    }

public static void stanfordNLPParser(String modifiedtext, String customStopWordList) throws Exception {

    Properties props = new Properties();

      props.setProperty("annotators", "tokenize, ssplit, pos, lemma, ner, parse, sentiment, regexner");
      props.setProperty("tokenize.language", "es");
      props.setProperty("tokenize.whitespace", "true");
      props.setProperty("regexner.mapping", "resources/customRegexNER.txt");

      String[] args = new String[] { "-props", "resources/tempaSmNER.prop" };
      CRFClassifier.main(args);
      props.setProperty("ner.model", "resources/ner-model.ser.gz");     

      StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
      List<CoreLabel> tokens = new ArrayList<CoreLabel>();

    /*Collections to store the processed N-gram token (nGram tokenizer does not allow the result to be stored as CoreLabel, as required for the pipeline)*/
    Collection<String> collectionOfProcessedTokens = new ArrayList<>();

    Annotation document = new Annotation(modifiedtext);
    pipeline.annotate(document);

      /*List of tokens (before performing the nGram operations)*/
      List<CoreLabel> tokensPreNgram = new ArrayList<CoreLabel>();
      List<CoreMap> sentences = document.get(CoreAnnotations.SentencesAnnotation.class);

      for (CoreMap sentence : sentences) {
      for (CoreLabel token : sentence.get(TokensAnnotation.class)) {                
          tokensPreNgram.add((CoreLabel) token);
        }

    Collection<String> tokenPreprocessor = StringUtils.getNgramsFromTokens(tokensPreNgram, 1, 6);
         for (String tokenNgramPostProcessor : tokenPreprocessor) {
           collectionOfProcessedTokens.add(tokenNgramPostProcessor.replaceAll(" ", "_"));                    
                   }

           CoreLabelTokenFactory string2CoreLabel = new CoreLabelTokenFactory();
         for (String temp : collectionOfProcessedTokens) {
           tokens.add(string2CoreLabel.makeToken(temp, temp, 0, 10));                    
         }


        for(CoreLabel token :tokens){

          System.out.println("For TEST: Current Token is  :" + token);          

          // generate Parts Of Speech
          String tokenPOS = token.get(PartOfSpeechAnnotation.class);
          System.out.println("For TEST: POS is   :" + quesGenPOS);

            if (token.get(PartOfSpeechAnnotation.class).matches(".*(WP).*")){ System.out.println(quesGentoken.get(TextAnnotation.class));}
          String tokenNER = token.get(NamedEntityTagAnnotation.class);
          String tokenSentiment = token.get(SentimentClass.class);
          String tokenlemma = token.get(LemmaAnnotation.class);

      }
    } 
  }

I am facing an null pointer exception at the place i'm performing an POS. While the token is generated correctly, the POS is throwing 'null'. I believe, there most be a problem in the way i construct the pipeline.

The java.lang.NullPointerException is @

`if (token.get(PartOfSpeechAnnotation.class).matches(".*(WP).*")){ System.out.println(quesGentoken.get(TextAnnotation.class));} 

because String tokenPOS = token.get(PartOfSpeechAnnotation.class); is not generating the POS

Any pointers as to why?