stanfordnlp/CoreNLP · error · RuntimeException

Output path already exists

Error message

Output path ${file} already exists

What it means

FileSystem.checkNotExistsOrFail(file) throws RuntimeException if the given file already exists, logging 'Output path <file> already exists'. It protects callers from overwriting prior outputs (and optional overwriting APIs from clobbering data).

Solutions

1. Delete or move the existing file/directory first, or pick a fresh output path (timestamp/uuid).
2. Rerun with output cleanup enabled in your pipeline.
3. Point the output to a different location and use the overwrite variant if you truly intend replacement.
4. Check the job that previously wrote there to avoid clobbering needed data.

Example fix

// before
FileSystem.checkNotExistsOrFail(out); // throws on rerun
// after
if (out.exists()) {
  java.nio.file.Files.move(out.toPath(), out.toPath().resolveSibling(out.getName() + ".bak"));
}
FileSystem.checkNotExistsOrFail(out);

if (file.exists()) {
  throw new IllegalStateException("Output already present, remove or rename: " + file);
}

try {
  FileSystem.checkNotExistsOrFail(out);
  runJob(out);
} catch (RuntimeException e) {
  log.warning("Output exists: " + e.getMessage());
}

When it happens

Trigger: Calling checkNotExistsOrFail on a path that is present: rerunning a job without cleaning output, a previous crashed run left partial files, or an output path colliding with an input path.

Common situations: Batch jobs restarted without clearing the output directory; timestamps/id collisions in generated filenames; user points --output at an existing file intentionally.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

• Cannot initialize logger!
• Collection elements must be Files or Strings
• Could not create
• Directory access problem for
• File doesn't exist

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/e3f95a74fc5310a8. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/io/FileSystem.java:143

      String error = "Could not create " + dir;
      log.info(error);
      throw new RuntimeException(error);
    }
  }

  public static void checkExistsOrFail(File file) {
    if (!file.exists()) {
      String error = "Output path " + file + " does not exist";
      log.info(error);
      throw new RuntimeException(error);
    }
  }

  public static void checkNotExistsOrFail(File file) {
    if (file.exists()) {
      String error = "Output path " + file + " already exists";
      log.info(error);
      throw new RuntimeException(error);
    }
  }

  /**
   * Unit test code
   */
  public static void main(String[] args) {
    String testDirName = "FileSystemTest";
    String testFileName = "Pair.java";
    
    File testDir = new File(testDirName);
    testDir.mkdir();
    
    try {
      copyFile(new File(testFileName),new File(testDirName + "/" + testFileName));
    } catch (RuntimeIOException e) {
      log.info("Copy failed");
      System.exit(-1);

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