title: Nullpointer exception during loading dependency parser
body: <p>I'm using stanford-corenlp-3.5.2 and the german parsing model germanFactored.ser.gz. The code works fine until I try to do dependency parsing. While initialilizing the <code>SemanticGraph</code> I retrieve a <code>NullPointerException</code>.</p>
  
  <p>Loading: CollapsedCCProcessedDependenciesAnnotation.class (the first line throws the exception)</p>
  
  <pre><code>SemanticGraph dependencies = sentence.get(CollapsedCCProcessedDependenciesAnnotation.class);
  System.out.println(dependencies);    
  dependencies.prettyPrint();
  </code></pre>
  
  <p>Whole code:</p>
  
  <pre><code>public static void main(String[] args) {
      Properties props = new Properties();
      props.put("annotators", "tokenize, ssplit, pos, lemma, ner, parse");
      props.put("parse.model", "edu/stanford/nlp/models/lexparser/germanFactored.ser.gz");
      props.put("ner.model", "edu/stanford/nlp/models/ner/german.dewac_175m_600.crf.ser.gz");
      props.put("pos.model", "edu/stanford/nlp/models/pos-tagger/german/german-hgc.tagger");
      props.put("parse.flags", "");
  
      StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
      String text = "Sehr gute Kenntnisse in Englisch und Deutsch sowie Programmierkenntnisse (C#, Java, C++).";                                                                                                                                              // text
      Annotation document = new Annotation(text);
      pipeline.annotate(document);
  
      List&lt;CoreMap&gt; sentences = document.get(SentencesAnnotation.class);
  
      for (CoreMap sentence : sentences) {
          for (CoreLabel token : sentence.get(TokensAnnotation.class)) {
              String word = token.get(TextAnnotation.class);
              String pos = token.get(PartOfSpeechAnnotation.class);
              String ne = token.get(NamedEntityTagAnnotation.class);
  
              System.out.println(String.format("%s - %s - %s", word, pos, ne));
          }
  
          Tree tree = sentence.get(TreeAnnotation.class);
          System.out.println(tree.toString());
  
          try {
              SemanticGraph dependencies = sentence.get(CollapsedCCProcessedDependenciesAnnotation.class);
              System.out.println(dependencies);
  
              dependencies.prettyPrint();
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  }
  </code></pre>