stanfordnlp/CoreNLP · error · RuntimeException

Cannot initialize logger!

Error message

Cannot initialize logger!

What it means

initializeAndRunCoref sets up a java.util.logging FileHandler writing to logFileName. Creating that handler can fail with SecurityException (security manager denies logging/file access) or IOException (bad path, unwritable directory), and the code wraps this in a RuntimeException 'Cannot initialize logger!' so startup aborts before any coreference processing.

Solutions

1. Ensure the directory of the configured log file exists and the process has write permission there
2. Use an absolute log file path, or point the log to a writable temp directory
3. Remove or elevate the SecurityManager restriction, or grant logging permission (e.g. FilePermission and LoggingPermission)
4. Catch the RuntimeException around initializeAndRunCoref and fall back to console logging (java.util.logging ConsoleHandler) instead of a file

Example fix

// before
coref.props: dcoref.log = logs/coref.log   // 'logs' does not exist
// after
// create the directory first, or use an absolute path
new File("logs").mkdirs();
props.setProperty("dcoref.log", "/var/log/coref/coref.log");

String logFile = props.getProperty("dcoref.log", "coref.log");
File f = new File(logFile);
File parent = f.getAbsoluteFile().getParentFile();
if (parent != null && !parent.isDirectory() && !parent.mkdirs())
  throw new IOException("Cannot create log dir: " + parent);
if (!f.getAbsolutePath().isEmpty() && f.exists() && !f.canWrite())
  throw new IOException("Log file not writable: " + f);

try {
  SieveCoreferenceSystem.runCoref(props);
} catch (RuntimeException e) {
  if (e.getMessage() != null && e.getMessage().contains("Cannot initialize logger")) {
    logger.addHandler(new ConsoleHandler()); // fallback to console logging
    logger.warning("File logging unavailable: " + e.getCause());
  } else throw e;
}

When it happens

Trigger: Running main with a log file path that points to a non-existent directory, an unwritable location, or when a SecurityManager blocks FileHandler creation; also if the log file is locked by another process on some platforms.

Common situations: Passing a -Ddcoref.log or properties log path with a directory that doesn't exist; running in a sandboxed/read-only deployment where the process cannot create files; relative log paths resolved against an unexpected working directory in a server or container.

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

• Unknown value for log.method
• Cannot initialize logger!
• Shouldn't happen:
• Error reading saved links
• RuntimeIOException wrapping IOException

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/53336214f60570d6. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/dcoref/SieveCoreferenceSystem.java:336

  public static String initializeAndRunCoref(Properties props) throws Exception {
    String timeStamp = Calendar.getInstance().getTime().toString().replaceAll("\\s", "-").replaceAll(":", "-");

    //
    // initialize logger
    //
    String logFileName = props.getProperty(Constants.LOG_PROP, "log.txt");
    if (logFileName.endsWith(".txt")) {
      logFileName = logFileName.substring(0, logFileName.length()-4) +"_"+ timeStamp+".txt";
    } else {
      logFileName = logFileName + "_"+ timeStamp+".txt";
    }
    try {
      FileHandler fh = new FileHandler(logFileName, false);
      logger.addHandler(fh);
      logger.setLevel(Level.FINE);
      fh.setFormatter(new NewlineLogFormatter());
    } catch (SecurityException | IOException e) {
      throw new RuntimeException("Cannot initialize logger!", e);
    }

    logger.fine(timeStamp);
    logger.fine(props.toString());
    Constants.printConstants(logger);

    // initialize coref system
    SieveCoreferenceSystem corefSystem = new SieveCoreferenceSystem(props);

    // MentionExtractor extracts MUC, ACE, or CoNLL documents
    MentionExtractor mentionExtractor;
    if (props.containsKey(Constants.MUC_PROP)){
      mentionExtractor = new MUCMentionExtractor(corefSystem.dictionaries, props,
                                                 corefSystem.semantics, corefSystem.singletonPredictor);
    } else if(props.containsKey(Constants.ACE2004_PROP) || props.containsKey(Constants.ACE2005_PROP)) {
      mentionExtractor = new ACEMentionExtractor(corefSystem.dictionaries, props,
                                                 corefSystem.semantics, corefSystem.singletonPredictor);
    } else if (props.containsKey(Constants.CONLL2011_PROP)) {

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