title: Using Stanford CoreNLP - Java heap space
body: <p>I am trying to use the coreference module of the Stanford CoreNLP pipeline, but I end up getting an OutOfMemory error in Java. I already increased the heap size (via Run->Run Configurations->VM Arguments in Eclipse) and set them to -Xmx3g -Xms1g. I even tried -Xmx12g -Xms4g, but that didn't help either. I'm using Eclipse Juno on OS X 10.8.5 with Java 1.6 on a 64-bit machine.
  Does anyone have an idea what else I could try?</p>
  
  <p>I'm using the example code from the website (<a href="http://nlp.stanford.edu/software/corenlp.shtml" rel="noreferrer">http://nlp.stanford.edu/software/corenlp.shtml</a>):</p>
  
  <pre><code>Properties props = new Properties();
  props.put("annotators", "tokenize, ssplit, pos, lemma, ner, parse, dcoref");
  StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
  
  String text = "Stanford University is located in California. It is a great university";
  
  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);       
    }
  
    Tree tree = sentence.get(TreeAnnotation.class);
    SemanticGraph dependencies = sentence.get(CollapsedCCProcessedDependenciesAnnotation.class);
  }
  
  Map&lt;Integer, CorefChain&gt; graph = document.get(CorefChainAnnotation.class);
  </code></pre>
  
  <p>And I get the error:</p>
  
  <pre><code>Adding annotator tokenize
  Adding annotator ssplit
  Adding annotator pos
  Reading POS tagger model from edu/stanford/nlp/models/pos-tagger/english-left3words/english-left3words-distsim.tagger ... done [0.9 sec].
  Adding annotator lemma
  Adding annotator ner
  Loading classifier from edu/stanford/nlp/models/ner/english.all.3class.distsim.crf.ser.gz ... done [3.1 sec].
  Initializing JollyDayHoliday for sutime
  Reading TokensRegex rules from edu/stanford/nlp/models/sutime/defs.sutime.txt
  Reading TokensRegex rules from edu/stanford/nlp/models/sutime/english.sutime.txt
  Jan 9, 2014 10:39:37 AM edu.stanford.nlp.ling.tokensregex.CoreMapExpressionExtractor appendRules
  INFO: Ignoring inactive rule: temporal-composite-8:ranges
  Reading TokensRegex rules from edu/stanford/nlp/models/sutime/english.holidays.sutime.txt
  Adding annotator dcoref
  Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
  at java.lang.String.substring(String.java:1939)
  at java.lang.String.subSequence(String.java:1972)
  at java.util.regex.Pattern.split(Pattern.java:1002)
  at java.lang.String.split(String.java:2292)
  at java.lang.String.split(String.java:2334)
  at edu.stanford.nlp.dcoref.Dictionaries.loadGenderNumber(Dictionaries.java:382)
  at edu.stanford.nlp.dcoref.Dictionaries.&lt;init&gt;(Dictionaries.java:553)
  at edu.stanford.nlp.dcoref.Dictionaries.&lt;init&gt;(Dictionaries.java:463)
  at edu.stanford.nlp.dcoref.SieveCoreferenceSystem.&lt;init&gt;(SieveCoreferenceSystem.java:282)
  at edu.stanford.nlp.pipeline.DeterministicCorefAnnotator.&lt;init&gt;(DeterministicCorefAnnotator.java:52)
  at edu.stanford.nlp.pipeline.StanfordCoreNLP$11.create(StanfordCoreNLP.java:775)
  at edu.stanford.nlp.pipeline.AnnotatorPool.get(AnnotatorPool.java:81)
  at edu.stanford.nlp.pipeline.StanfordCoreNLP.construct(StanfordCoreNLP.java:260)
  at edu.stanford.nlp.pipeline.StanfordCoreNLP.&lt;init&gt;(StanfordCoreNLP.java:127)
  at edu.stanford.nlp.pipeline.StanfordCoreNLP.&lt;init&gt;(StanfordCoreNLP.java:123)
  at extraction.BaselineApproach.main(BaselineApproach.java:88)
  </code></pre>