languagetool-org/languagetool · error · RuntimeException

Could not check text in file

Error message

Could not check text in file <file>

What it means

Main.runRecursive/runRecursiveFile wraps any Exception thrown while checking a file (or line within a file) into a RuntimeException with this message. It is a generic catch-all in the command-line client: whatever went wrong while reading or checking the file is preserved as the cause. It means LanguageTool could not complete the check of the given file.

Solutions

1. Read the 'Caused by' of the printed stack trace — this message only wraps the real failure.
2. Verify the --encoding flag matches the file's actual charset (e.g. UTF-8 vs ISO-8859-1).
3. Check the file is readable by the current user and not empty/corrupt (file, iconv, or head).
4. If running recursively, exclude binary/unwanted files and retry on the single failing file to isolate it.

Example fix

// before
languagetool -l en -c ASCII report.txt
// after
languagetool -l en -c UTF-8 report.txt

File f = new File(path);
if (!f.isFile() || !f.canRead()) throw new IllegalArgumentException("unreadable file: " + path);

try {
  prg.runOnFile(file.getAbsolutePath(), encoding, xmlFiltering);
} catch (RuntimeException e) {
  log("File check failed: " + file + ", cause=" + e.getCause(), e);
}

When it happens

Trigger: Running `languagetool` CLI with a file (or -r recursive directory) when an exception occurs inside runOnFile/runOnFileLineByLine: unreadable or non-UTF-8 file with wrong --encoding, malformed input, or any rule/loader exception during the check.

Common situations: Wrong --encoding option for the actual file encoding; file deleted or made unreadable between discovery and check; a broken custom rule or language module throwing during analysis; recursive scan hitting a binary/locked file.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• Could not create LanguageTool instance for language
• Applying suggestions makes no sense for profiling
• Cannot use --premiumAlways with non-premium version
• Could not activate rules
• Could not get rules of language

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/c55c7dbcaadab16b. Report an issue: GitHub.

Appendix: source

Thrown at languagetool-commandline/src/main/java/org/languagetool/commandline/Main.java:329

  private void runRecursive(String filename, String encoding, boolean xmlFiltering, JLanguageTool.Level level) {
    File dir = new File(filename);
    File[] files = dir.listFiles();
    if (files == null) {
      throw new IllegalArgumentException(dir.getAbsolutePath() + " is not a directory, cannot use recursion");
    }
    for (File file : files) {
      try {
        if (file.isDirectory()) {
          runRecursive(file.getAbsolutePath(), encoding, xmlFiltering, level);
        } else {
          if (options.isLineByLine()) {
            runOnFileLineByLine(file.getAbsolutePath(), encoding, level);
          } else {
            runOnFile(file.getAbsolutePath(), encoding, xmlFiltering);
          }
        }
      } catch (Exception e) {
        throw new RuntimeException("Could not check text in file " + file, e);
      }
    }    
  }

  /**
   * Loads filename and filters out XML. Note that the XML
   * filtering can lead to incorrect positions in the list of matching rules.
   */
  private String getFilteredText(String filename, String encoding, boolean xmlFiltering) throws IOException {
    if (options.isVerbose()) {
      lt.setOutput(System.err);
    }
    // don't use StringTools.readStream() as that might add newlines which aren't there:
    try (InputStreamReader reader = getInputStreamReader(filename, encoding)) {
      String fileContents = readerToString(reader);
      if (xmlFiltering) {
        return filterXML(fileContents);
      } else {

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