stanfordnlp/CoreNLP · error · IllegalArgumentException

Need to specify -testTreebank

Error message

Need to specify -testTreebank

What it means

FindNearestNeighbors needs a test treebank of gold trees to parse and query for nearest neighbors. When -testTreebank is not supplied, main() throws this IllegalArgumentException. It is a required-input check performed before model loading.

Solutions

1. Pass -testTreebank <path-to-treebank-file> pointing at gold trees
2. Ensure the path exists and is readable (the error fires before the file is opened, so fix the flag first)
3. Provide all three required flags together: -model, -testTreebank, -output

Example fix

// before
-Dmodel=dvparser.ser.gz ... FindNearestNeighbors -output out.txt
// after
FindNearestNeighbors -model dvparser.ser.gz -testTreebank test.gold -output out.txt

if (!Arrays.asList(args).contains("-testTreebank")) {
  throw new IllegalArgumentException("FindNearestNeighbors requires -testTreebank <goldTrees>");
}

try {
  FindNearestNeighbors.main(args);
} catch (IllegalArgumentException e) {
  System.err.println("Missing required option: " + e.getMessage());
}

When it happens

Trigger: Running FindNearestNeighbors.main() with -model and -output set but no -testTreebank flag, leaving testTreebankPath null.

Common situations: Omitting the treebank when experimenting with small inputs; assuming a default evaluation set; typo-ing the flag (e.g. -test_treebank).

Understand the failure class

Background: "Must pass :limit option" / "Missing required option" — required option errors explained — this error's family across 41 libraries.

Related errors

• 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…
• -labels is required

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/63b8cb0322229d63. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/parser/dvparser/FindNearestNeighbors.java:91

        argIndex += 2;
      } else if (args[argIndex].equalsIgnoreCase("-testTreebank")) {
        Pair<String, FileFilter> treebankDescription = ArgUtils.getTreebankDescription(args, argIndex, "-testTreebank");
        argIndex = argIndex + ArgUtils.numSubArgs(args, argIndex) + 1;
        testTreebankPath = treebankDescription.first();
        testTreebankFilter = treebankDescription.second();
      } else if (args[argIndex].equalsIgnoreCase("-output")) {
        outputPath = args[argIndex + 1];
        argIndex += 2;
      } else {
        unusedArgs.add(args[argIndex++]);
      }
    }

    if (modelPath == null) {
      throw new IllegalArgumentException("Need to specify -model");
    }
    if (testTreebankPath == null) {
      throw new IllegalArgumentException("Need to specify -testTreebank");
    }
    if (outputPath == null) {
      throw new IllegalArgumentException("Need to specify -output");
    }

    String[] newArgs = unusedArgs.toArray(new String[unusedArgs.size()]);

    LexicalizedParser lexparser = LexicalizedParser.loadModel(modelPath, newArgs);

    Treebank testTreebank = null;
    if (testTreebankPath != null) {
      log.info("Reading in trees from " + testTreebankPath);
      if (testTreebankFilter != null) {
        log.info("Filtering on " + testTreebankFilter);
      }
      testTreebank = lexparser.getOp().tlpParams.memoryTreebank();;
      testTreebank.loadPath(testTreebankPath, testTreebankFilter);
      log.info("Read in " + testTreebank.size() + " trees for testing");

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