stanfordnlp/CoreNLP · error · RuntimeException

unable to find sentences in

Error message

unable to find sentences in: ${annotation}

What it means

An IllegalStateException precondition check in NumberAnnotator.annotate: the input Annotation lacks the SentencesAnnotation key, meaning sentence splitting must run before the number annotator; the annotation object is at fault.

Solutions

1. Include 'tokenize,ssplit' before 'number' in the annotators property
2. Ensure TokensAnnotation is populated (run a tokenizer) before invoking the annotator
3. Use the full StanfordCoreNLP pipeline rather than instantiating NumberAnnotator directly

Example fix

// before
props.setProperty("annotators", "number");
// after
props.setProperty("annotators", "tokenize,ssplit,number");

if (!annotation.containsKey(CoreAnnotations.TokensAnnotation.class) && !annotation.containsKey(CoreAnnotations.SentencesAnnotation.class)) { pipeline.annotate(annotation); }

try { numberAnnotator.annotate(annotation); } catch (RuntimeException e) { if (e.getMessage().contains("unable to find sentences")) { tokenizeAndSplit(annotation); numberAnnotator.annotate(annotation); } else throw e; }

When it happens

Trigger: Invoking NumberAnnotator.annotate() on an Annotation lacking both SentencesAnnotation and TokensAnnotation, i.e. the text was never tokenized or sentence-split.

Common situations: Running the 'number' annotator standalone without prerequisite annotators; manually constructing an Annotation from a String without running tokenize/ssplit first.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Unable to find words/tokens in
• ERROR: Relation extraction requires full syntactic analysis!
• Expected tree labels to have their heads assigned. Failed…
• unable to find words/tokens in
• CoreMap must have either a Calendar or DocDate annotation

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/542710d9b431cf21. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/pipeline/NumberAnnotator.java:86

  public void annotate(Annotation annotation) {
    if (VERBOSE) {
      log.info("Adding number annotation ... ");
    }

    if (annotation.containsKey(CoreAnnotations.SentencesAnnotation.class)) {
      // classify tokens for each sentence
      for (CoreMap sentence : annotation.get(CoreAnnotations.SentencesAnnotation.class)) {
        List<CoreLabel> tokens = sentence.get(CoreAnnotations.TokensAnnotation.class);
        doOneSentenceNew(tokens, annotation, sentence);
      }
      if (VERBOSE) {
        log.info("done. Output: " + annotation.get(CoreAnnotations.SentencesAnnotation.class));
      }
    } else if (annotation.containsKey(CoreAnnotations.TokensAnnotation.class)) {
      List<CoreLabel> tokens = annotation.get(CoreAnnotations.TokensAnnotation.class);
      doOneSentenceNew(tokens, annotation, null);
    } else {
      throw new RuntimeException("unable to find sentences in: " + annotation);
    }
  }

  private void doOneSentenceNew(List<CoreLabel> words, Annotation doc, CoreMap sentence) {
    List<CoreLabel> newWords = NumberSequenceClassifier.copyTokens(words, sentence);

    nsc.classifyWithGlobalInformation(newWords, doc, sentence);

    Iterator<? extends CoreLabel> newFLIter = newWords.iterator();
    for (CoreLabel origWord : words) {
      CoreLabel newWord = newFLIter.next();
      String before = origWord.ner();
      String newGuess = newWord.get(CoreAnnotations.AnswerAnnotation.class);
      // log.info(origWord.word());
      // log.info(origWord.ner());
      if (VERBOSE)
        log.info(newWord);
      // log.info("-------------------------------------");

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