stanfordnlp/CoreNLP · error · java.lang.IllegalArgumentException

Need to supply a treebank with -treebank

Error message

Need to supply a treebank with -treebank

What it means

CacheParseHypotheses.main throws IllegalArgumentException when the parsed treebank list is empty, meaning no -treebank argument was given. The tool needs source trees to generate hypothesis trees for, so it cannot proceed without one. This is the third mandatory-argument check in main.

Solutions

1. Add -treebank /path/to/treebank (e.g. a Penn Treebank file) to the command line
2. Verify the flag spelling is exactly -treebank
3. Confirm the treebank path exists and is readable

Example fix

// before
java edu.stanford.nlp.parser.dvparser.CacheParseHypotheses -model parser.ser.gz -output out.txt.gz
// after
java edu.stanford.nlp.parser.dvparser.CacheParseHypotheses -model parser.ser.gz -output out.txt.gz -treebank wsj-train.txt

List<String> args = Arrays.asList(cmdArgs);
if (!args.contains("-treebank")) {
    throw new IllegalArgumentException("CacheParseHypotheses requires -treebank <path>");
}

try {
    CacheParseHypotheses.main(args);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("-treebank")) {
        System.err.println("Usage: add -treebank /path/to/treebank.txt");
    }
}

When it happens

Trigger: Running CacheParseHypotheses with -model and -output but no -treebank flag, or passing -treebank with no following path so the collection ends up empty.

Common situations: Omitting the treebank path in scripted invocations; pointing at a flag-only argument; misunderstanding that the treebank must be supplied as a file path (optionally with file ranges like file.txt 0 100).

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

• Need to supply a parser model with -model
• Need to supply an output filename with -output
• Found an argument -baseModels with no actual models named
• Need to specify -model to load an already prepared…
• Please specify either -file, -fileList or -stdin

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/d2637398cffc82d7. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/parser/dvparser/CacheParseHypotheses.java:239

        treebanks.add(treebankDescription);
        continue;
      }
      if (args[argIndex].equalsIgnoreCase("-numThreads")) {
        numThreads = Integer.parseInt(args[argIndex + 1]);
        argIndex += 2;
        continue;
      }
      throw new IllegalArgumentException("Unknown argument " + args[argIndex]);
    }

    if (parserModel == null) {
      throw new IllegalArgumentException("Need to supply a parser model with -model");
    }
    if (output == null) {
      throw new IllegalArgumentException("Need to supply an output filename with -output");
    }
    if (treebanks.isEmpty()) {
      throw new IllegalArgumentException("Need to supply a treebank with -treebank");
    }

    log.info("Writing output to " + output);
    log.info("Loading parser model " + parserModel);
    log.info("Writing " + dvKBest + " hypothesis trees for each tree");

    LexicalizedParser parser = LexicalizedParser.loadModel(parserModel, "-dvKBest", Integer.toString(dvKBest));
    CacheParseHypotheses cacher = new CacheParseHypotheses(parser);
    TreeTransformer transformer = DVParser.buildTrainTransformer(parser.getOp());
    List<Tree> sentences = new ArrayList<>();
    for (Pair<String, FileFilter> description : treebanks) {
      log.info("Reading trees from " + description.first);
      Treebank treebank = parser.getOp().tlpParams.memoryTreebank();
      treebank.loadPath(description.first, description.second);

      treebank = treebank.transform(transformer);
      sentences.addAll(treebank);
    }

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