stanfordnlp/CoreNLP · error · java.lang.RuntimeException

Error parsing file:

Error message

Error parsing file: 

What it means

createExtractorFromFiles wraps any exception raised while reading and parsing a TokensRegex rules file into a RuntimeException with this message. It is a generic wrapper: the cause (ex) holds the real parser error, usually a syntax error in the .rules file.

Solutions

1. Inspect the cause exception (ex.getCause()) for the exact line/column of the grammar error
2. Validate the rules file syntax ( braces, semicolons, rule options) against TokensRegex grammar
3. Verify the file path is readable and the classpath/resource string is correct
4. Check rule constructs against your CoreNLP version's grammar

Example fix

// before: cause hidden
try { extractor = createExtractorFromFiles(env, files); } catch (RuntimeException e) { e.printStackTrace(); }
// after
try { extractor = createExtractorFromFiles(env, files); } catch (RuntimeException e) { logger.error("rule parse failed", e.getCause()); }

File f = new File(rulesPath);
if (!f.canRead()) throw new IOException("Rules file not readable: " + rulesPath);
// optional pre-check: file non-empty
if (f.length() == 0) throw new IOException("Empty rules file: " + rulesPath);

try { extractor = CoreMapExpressionExtractor.getExtractorFromFiles(env, files); } catch (RuntimeException e) { Throwable cause = e.getCause(); throw new IllegalStateException("TokensRegex rule parse failed: " + (cause != null ? cause.getMessage() : e.getMessage()), cause); }

When it happens

Trigger: Calling CoreMapExpressionExtractor.createExtractorFromFiles(env, filenames) where a rules file has TokensRegex syntax errors, cannot be read, or the parser (TokenSequenceParser) rejects a construct.

Common situations: Malformed rule grammar (missing braces/semicolons), undefined variables or options in the rules file, wrong file path/encoding, or rules written for a different CoreNLP version.

Understand the failure class

Background: "Config file not found": what it means and how to fix it in docker-sync, Maven, Vagrant, Turborepo and other tools — this error's family across 60 libraries.

Related errors

• Invalid value for key:
• Unknown annotation key:
• Error parsing to node pattern
• Error parsing to sequence pattern
• Parsing failed. Error:

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/220a4905f3dcbab6. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/ling/tokensregex/CoreMapExpressionExtractor.java:294

    return createExtractorFromFiles(env, Arrays.asList(filenames));
  }

  /**
   * Creates an extractor using the specified environment, and reading the rules from the given filenames.
   * @param env
   * @param filenames
   * @throws RuntimeException
   */
  public static <M extends MatchedExpression> CoreMapExpressionExtractor<M> createExtractorFromFiles(Env env, List<String> filenames) throws RuntimeException {
    CoreMapExpressionExtractor<M> extractor = new CoreMapExpressionExtractor<>(env);
    for (String filename:filenames) {
      try (BufferedReader br = IOUtils.readerFromString(filename)) {
        if (verbose)
          log.info("Reading TokensRegex rules from " + filename);
        TokenSequenceParser parser = new TokenSequenceParser();
        parser.updateExpressionExtractor(extractor, br);
      } catch (Exception ex) {
        throw new RuntimeException("Error parsing file: " + filename, ex);
      }
    }
    return extractor;
  }

  /**
   * Creates an extractor using the specified environment, and reading the rules from the given filename.
   * @param env
   * @param filename
   * @throws RuntimeException
   */
  public static CoreMapExpressionExtractor createExtractorFromFile(Env env, String filename) throws RuntimeException {
    return createExtractorFromFiles(env, Collections.singletonList(filename));
  }

  /**
   * Creates an extractor using the specified environment, and reading the rules from the given string
   * @param env

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