stanfordnlp/CoreNLP · error · RuntimeException

args: treebankPath trainNums testNums

Error message

args: treebankPath trainNums testNums

What it means

The CharacterLevelTagExtender main() requires exactly three command-line arguments: a treebank path, training file numbers, and test file numbers. When the argument count differs from 3, it deliberately aborts with this RuntimeException rather than guessing the caller's intent. It is a usage-guard error thrown before any parsing work begins.

Solutions

1. Pass exactly three arguments: treebankPath, trainNums, testNums, e.g. java CharacterLevelTagExtender /data/ctb 001-050 051-100
2. Quote any path containing spaces so it counts as one argument
3. Check the class's usage comments to confirm the expected invocation
4. Wrap the tool in a script that validates argument count before invoking the JVM

Example fix

// before
java CharacterLevelTagExtender /data/ctb 100
// after
java CharacterLevelTagExtender /data/ctb 001-100 101-150

if (args == null || args.length != 3) {
  System.err.println("usage: treebankPath trainNums testNums");
  System.exit(2);
}

boolean hasValidArgs(String[] args) { return args != null && args.length == 3; }

When it happens

Trigger: Running CharacterLevelTagExtender as a Java main class with fewer or more than 3 args, e.g. java edu.stanford.nlp.trees.international.pennchinese.CharacterLevelTagExtender /path/to/treebank 100 (missing testNums), or passing extra flags; a path containing unquoted spaces also splits into extra args and inflates the count.

Common situations: Command-line invocations of the Penn Chinese treebank tooling from shell scripts or docs where arguments were copied incompletely, or where a path containing unquoted spaces splits into multiple args and inflates the count.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Cannot find or open + sentFileName
• Error: No dest file provided in properties or via command…
• Error: No training file provided in properties or via…
• Error: No training file provided in properties or via…
• Error: -train option must have treebankPath as first…

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/6d5abf26da5b8b0e. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/trees/international/pennchinese/CharacterLevelTagExtender.java:145

        pw.println("NOT EQUAL AFTER UNTRANSFORMATION!!!");
        pw.println();
        oldTree.pennPrint(pw);
        pw.println();
        tree.pennPrint(pw);
        pw.println("------------------");
      }
    }
  }

  /**
   * for testing -- CURRENTLY BROKEN!!!
   *
   * @param args input dir and output filename
   * @throws IOException
   */
  public static void main(String[] args) throws IOException {
    if (args.length != 3) {
      throw new RuntimeException("args: treebankPath trainNums testNums");
    }

    ChineseTreebankParserParams ctpp = new ChineseTreebankParserParams();
    ctpp.charTags = true;
    // TODO: these options are getting clobbered by reading in the
    // parser object (unless it's a text file parser?)
    Options op = new Options(ctpp);
    op.doDep = false;
    op.testOptions.maxLength = 90;

    LexicalizedParser lp;
    try {
      FileFilter trainFilt = new NumberRangesFileFilter(args[1], false);

      lp = LexicalizedParser.trainFromTreebank(args[0], trainFilt, op);
      try {
        String filename = "chineseCharTagPCFG.ser.gz";
        log.info("Writing parser in serialized format to file " + filename + " ");

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