stanfordnlp/CoreNLP · critical · RuntimeIOException

Error opening output file

Error message

Error opening output file

What it means

DependencyParser.test() wraps any IOException from opening the output writer (a file via 'outFile' or stdout) in a RuntimeIOException with this message. If the parser cannot open the destination for parse results, the test run aborts before parsing begins.

Solutions

1. Create the output file's parent directory before running (mkdir -p).
2. Ensure the output path points to a writable regular file, not a directory.
3. Check write permissions on the target directory/user.
4. Omit -outFile to write to stdout and redirect output yourself.

Example fix

// before
-outFile /nonexistent/dir/parsed.conll
// after
mkdir -p /out && -outFile /out/parsed.conll

java.io.File out = new java.io.File(outFilePath);
if (outFilePath != null && !outFilePath.equals("-")) {
    java.io.File parent = out.getAbsoluteFile().getParentFile();
    if (parent == null || !parent.isDirectory() || !parent.canWrite())
        throw new IllegalArgumentException("Output directory missing or unwritable: " + parent);
}

try {
    parser.test(props, "-textFile", in, "-outFile", out);
} catch (RuntimeIOException e) {
    // inspect cause: output file open failure
}

When it happens

Trigger: Setting the outFile property/-outFile flag to a path in a nonexistent directory, a read-only location, or one requiring permissions the process lacks; an IO error while wrapping System.out.

Common situations: Output directory does not exist, output path is a directory rather than a file, disk is full or read-only mount, running under a user without write permission.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• Error creating data exporter
• Serializing classifier to
• No input file provided (use -textFile)
• RuntimeIOException wrapping IOException from write
• Exception in printToFile " + file.getAbsolutePath()

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/2594c65459558701. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/parser/nndep/DependencyParser.java:1330

      String encoding = parser.config.tlp.getEncoding();
      String inputFilename = props.getProperty("textFile");
      BufferedReader input;
      try {
        input = inputFilename.equals("-")
                ? IOUtils.readerFromStdin(encoding)
                : IOUtils.readerFromString(inputFilename, encoding);
      } catch (IOException e) {
        throw new RuntimeIOException("No input file provided (use -textFile)", e);
      }

      String outputFilename = props.getProperty("outFile");
      PrintWriter output;
      try {
        output = outputFilename == null || outputFilename.equals("-")
            ? IOUtils.encodedOutputStreamPrintWriter(System.out, encoding, true)
            : IOUtils.getPrintWriter(outputFilename, encoding);
      } catch (IOException e) {
        throw new RuntimeIOException("Error opening output file", e);
      }

      parser.parseTextFile(input, output);
    }
  }

}

View on GitHub (pinned to 1b7edd19c4)