languagetool-org/languagetool · error · IOException

Cannot load or parse '" + filename + "'

Error message

Cannot load or parse '" + filename + "'

What it means

BitextPatternRuleLoader.getRules wraps any exception from SAX parsing or rule-building of a bitext rule file into an IOException with the message "Cannot load or parse '<filename>'" and the original exception as cause. It is a catch-all conversion: the real problem (malformed XML, unsupported element, IO error) is in the cause chain. The loader is called by getBitextRules when loading bilingual pattern rules.

Source

Thrown at languagetool-core/src/main/java/org/languagetool/rules/patterns/bitext/BitextPatternRuleLoader.java:48

/**
 * Loads {@link PatternRule}s from an XML file.
 * 
 * @author Marcin Miłkowski
 */
public class BitextPatternRuleLoader extends DefaultHandler {

  public final List<BitextPatternRule> getRules(InputStream is, String filename) throws IOException {
    List<BitextPatternRule> rules;
    try {
      BitextPatternRuleHandler handler = new BitextPatternRuleHandler();
      SAXParserFactory factory = SAXParserFactory.newInstance();
      SAXParser saxParser = factory.newSAXParser();
      saxParser.getXMLReader().setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
      saxParser.parse(is, handler);
      rules = handler.getBitextRules();
      return rules;
    } catch (Exception e) {
      throw new IOException("Cannot load or parse '" + filename + "'", e);
    }
  }

}

View on GitHub (pinned to 2e990059ce)

Solutions

1. Read the 'Caused by' chain of the IOException to find the real parse error and its line number
2. Validate the bitext XML file with an XML parser/linter before loading
3. Check that the filename/path is correct and the InputStream is readable and not already consumed
4. Remove bitext-unsupported elements (e.g. triggers_error) revealed by the cause

Example fix

// before
try (InputStream is = new FileInputStream("rules.xml")) { ... }
// after: verify cause and file existence first
File f = new File("rules.xml");
if (!f.isFile()) throw new FileNotFoundException("rules.xml");
try (InputStream is = new FileInputStream(f)) { loader.getRules(is, "rules.xml"); }

File f = new File(filename);
if (!f.isFile() || !f.canRead()) throw new FileNotFoundException(filename);
try (InputStream probe = new FileInputStream(f)) {
  DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(probe); // fail fast on malformed XML
}

try {
  rules = BitextPatternRuleLoader.getBitextRules(stream, filename, srcLang, trgLang);
} catch (IOException e) {
  Throwable cause = e.getCause();
  log.error("Failed to load bitext rules from " + filename + ": " + cause, e);
  if (cause instanceof SAXException) { /* point author at line/column */ }
}

When it happens

Trigger: Any failure during factory.newSAXParser(), saxParser.parse(is, handler), or handler.getBitextRules() — e.g. malformed XML, bitext-unsupported elements like triggers_error, or a broken input stream — inside the try block.

Common situations: Malformed or hand-edited bitext rule XML; missing file/stream miswired so parse fails; using bitext-unsupported features; XML parser feature misconfiguration.

Related errors

• 'triggers_error' is not supported for bitext XML
• Could not tag and disambiguate '<token>'
• JSON output format is not implemented for Bitext
• You have to set the source language (as mother tongue) in bi
• Format error in file ${path}, line: ${line}

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/24d6cf99c08f9ae9. Report an issue: GitHub.