stanfordnlp/CoreNLP · error · RuntimeException

Unable to annotate attribute " + key

Error message

Unable to annotate attribute " + key

What it means

ChunkAnnotationUtils.annotateWithMatchingFields maps attribute name/value strings onto CoreMap annotation keys via reflection (key class lookup plus a valueOf(String) method). Any failure in that reflective pipeline is rethrown as RuntimeException('Unable to annotate attribute ' + key, ex), preserving the cause.

Solutions

1. Inspect the wrapped cause (ex) to see whether key lookup or valueOf parsing failed
2. Correct the attribute key to a valid CoreAnnotations class name
3. Ensure the value string parses for the key's type (e.g. valid integer for an Integer key)
4. Verify the annotation classes are on the classpath

Example fix

// before
attributes.put("Position", "abc"); // Position is Integer
// after
attributes.put("Position", "5");

for (Map.Entry<String,String> e : attributes.entrySet()) {
  if (EnvLookup.lookupAnnotationKeyWithClassname(null, e.getKey()) == null)
    throw new IllegalArgumentException("Unknown annotation key: " + e.getKey());
}

try {
  ChunkAnnotationUtils.annotateChunk(chunk, attributes);
} catch (RuntimeException e) {
  if (e.getMessage().startsWith("Unable to annotate attribute")) {
    log("bad attribute: " + e.getMessage(), e.getCause());
  } else throw e;
}

When it happens

Trigger: Calling annotateChunk/annotateChunks with an attributes map whose key does not resolve to a valid annotation key class, or whose value cannot be parsed by that key class's valueOf(String) method (e.g. 'MyCoreMap=not-a-number' for an integer key).

Common situations: Typo'd annotation key names in config; value strings of the wrong format for the target type; annotation class not on the classpath; passing custom keys unsupported by EnvLookup.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Unknown field for type , trying to set to
• Incompatible type for type , trying to set to
• Expected parsers with DVModel embedded
• This parser does not contain a DVModel reranker
• Unknown null attribute.

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/00a2b7244863309f. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/pipeline/ChunkAnnotationUtils.java:860

  public static void annotateChunk(CoreMap chunk, Map<String,String> attributes) {
    for (Map.Entry<String, String> entry : attributes.entrySet()) {
      String key = entry.getKey();
      String value = entry.getValue();
      Class coreKeyClass = AnnotationLookup.toCoreKey(key);
      if (key != null) {
        if (value != null)  {
          try {
            Class valueClass = AnnotationLookup.getValueType(coreKeyClass);
            if (valueClass == String.class) {
              chunk.set(coreKeyClass, value);
            } else {
             Method valueOfMethod = valueClass.getMethod("valueOf", String.class);
              if (valueOfMethod != null) {
                chunk.set(coreKeyClass, valueOfMethod.invoke(valueClass, value));
              }
            }
          } catch (Exception ex) {
            throw new RuntimeException("Unable to annotate attribute " + key, ex);
          }
        } else {
          chunk.set(coreKeyClass, null);
        }
      } else {
        throw new UnsupportedOperationException("Unknown null attribute.");
      }
    }
  }

  public static void annotateChunks(List<? extends CoreMap> chunks, int start, int end, Map<String,String> attributes) {
    for (int i = start; i < end; i++) {
      annotateChunk(chunks.get(i), attributes);
    }
  }

  public static void annotateChunks(List<? extends CoreMap> chunks, Map<String,String> attributes) {
    for (CoreMap chunk:chunks) {

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