stanfordnlp/CoreNLP · error · RuntimeException

Please specify coref.algorithm.class

Error message

Please specify coref.algorithm.class

What it means

CorefAlgorithm.fromProps dispatches on coref.algorithm (clustering/statistical/neural/fastneural); this error fires when the property coref.algorithm.class is missing and no built-in algorithm type matches, so the factory cannot instantiate a coreference algorithm.

Solutions

1. Set -coref.algorithm.class to a CorefAlgorithm implementation class name
2. Or choose a built-in algorithm (statistical, neural, fastneural, clustering) via coref.algorithm

When it happens

Trigger: Thrown at src/edu/stanford/nlp/coref/CorefAlgorithm.java:42 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/4eb13ae0f6604697. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/coref/CorefAlgorithm.java:42

  static CorefAlgorithm fromProps(Properties props, Dictionaries dictionaries) {
    CorefAlgorithmType algorithm = CorefProperties.algorithm(props);
    if (algorithm == CorefAlgorithmType.CLUSTERING) {
      return new ClusteringCorefAlgorithm(props, dictionaries);
    } else if (algorithm == CorefAlgorithmType.STATISTICAL) {
      return new StatisticalCorefAlgorithm(props, dictionaries);
    } else if (algorithm == CorefAlgorithmType.NEURAL) {
      return new NeuralCorefAlgorithm(props, dictionaries);
    } else if (algorithm == CorefAlgorithmType.FASTNEURAL) {
      return new FastNeuralCorefAlgorithm(props, dictionaries);
    } else if (algorithm == CorefAlgorithmType.CUSTOM) {
      String classname = PropertiesUtils.getString(props, "coref.algorithm.class", null);
      try {
        if (classname != null) {
          Class clazz = Class.forName(classname);
          return (CorefAlgorithm) clazz.getConstructor(Properties.class, Dictionaries.class).newInstance(props, dictionaries);
        } else {
          throw new RuntimeException("Please specify coref.algorithm.class");
        }
      } catch (Exception e) {
        throw new RuntimeException("Error creating custom coref system", e);
      }
    } else {
      try {
        return new HybridCorefSystem(props, dictionaries);
      } catch (Exception e) {
        throw new RuntimeException("Error creating hybrid coref system", e);
      }
    }
  }

}

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