stanfordnlp/CoreNLP · error · RuntimeException

Error annotating

Error message

Error annotating ${file.getAbsoluteFile()}

What it means

In the multi-file/batch annotate path (annotateFiles-style), when annotating an input file throws and the run is configured to stop on error (clearPool true), the worker wraps the cause in RuntimeException 'Error annotating <file>'. It identifies which file failed while preserving the underlying exception.

Solutions

1. Inspect the cause (ex) attached to the RuntimeException - fix the underlying annotation failure for that file.
2. Validate/pre-filter input files (non-empty, valid encoding) before batch annotation.
3. Configure the run to continue on error instead of clearing the pool, and log/skip the bad file.
4. Increase memory (-Xmx) or split very large files if the cause is resource exhaustion.

Example fix

// before
// batch annotate crashes whole run on one bad file
pipeline.annotate(files);
// after
for (CoreDocument doc : docs) {
  try { pipeline.annotate(doc); }
  catch (Exception e) { log.warn("Skipping bad document", e); }
}

for (File f : inputFiles) {
  if (!f.isFile() || f.length() == 0) log.warn("Skipping empty/invalid file: " + f);
}

try {
  pipeline.annotate(annotation);
} catch (RuntimeException e) {
  if (e.getMessage() != null && e.getMessage().startsWith("Error annotating ")) {
    log.error("Failed on {} cause {}", e.getMessage(), e.getCause());
  } else throw e;
}

When it happens

Trigger: Running pipeline.annotate over a collection/directory of files with -replaceInput/-outputExtension style batch processing; one document makes an annotator throw (e.g. tokenizer or parse failure, malformed encoding, empty/garbage input) and requireException/clearPool is set.

Common situations: Batch-annotating a mixed corpus where one file has corrupt encoding or an empty body; out-of-memory or thread-pool issues on huge files; model files missing so an annotator throws on first document.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

• addFeature was called with a features object that is…
• adjustFinalToken: Unexpected final char: |
• after W derivative, index() != x.length()
• An error occurred while testing the tagger.
• Annotation field cannot be null

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/077c880c3ce48676. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/pipeline/StanfordCoreNLP.java:1402

            synchronized (totalErrorAnnotating) {
              totalErrorAnnotating.incValue(1);
              // check we've processed or errored on every file, handle tasks to run after last document
              if ((totalProcessed.intValue() + totalErrorAnnotating.intValue()) == files.size()) {
                // clear pool if necessary
                if (clearPool)
                  GLOBAL_ANNOTATOR_CACHE.clear();
                // print out timing info
                if (TIME && pipeline.isPresent() && tim.isPresent())
                  logTimingInfo(pipeline.get(), tim.get());
              }
            }

          } else {
            // if stopping due to error, make sure to clear the pool
            if (clearPool) {
              GLOBAL_ANNOTATOR_CACHE.clear();
            }
            throw new RuntimeException("Error annotating " + file.getAbsoluteFile(), ex);
          }
        });

      } catch (IOException e) {
        throw new RuntimeIOException(e);
      }

    }
  }

  public void processFiles(final Collection<File> files, int numThreads, boolean clearPool, Optional<Timing> tim) throws IOException {
    processFiles(null, files, numThreads, clearPool, tim);
  }

  public void processFiles(final Collection<File> files, boolean clearPool, Optional<Timing> tim) throws IOException {
    processFiles(files, 1, clearPool, tim);
  }

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