stanfordnlp/CoreNLP · error · IllegalStateException

Could not find java.util.logging in your classpath

Error message

Could not find java.util.logging in your classpath

What it means

Handlers.javaUtil Thunk wraps construction of a JavaUtilLoggingHandler; any Exception during creation is rethrown as this IllegalStateException. Despite the message, java.util.logging is part of the JDK, so failures are almost always reflective/linkage errors in exotic environments.

Solutions

1. Check the cause chain to see the actual class that failed to load; in modern JDKs java.util.logging is always present, so suspect the classloader.
2. Switch to Handlers.stderr or Handlers.output which need no java.util.logging.
3. If running a custom runtime image, include the java.logging module (jlink --add-modules java.logging).
4. Initialize java.util.logging (LogManager) once early to surface the real underlying error.

Example fix

// before
RedwoodConfiguration.empty().handlers(Handlers.javaUtil).apply();
// after
RedwoodConfiguration.empty().handlers(Handlers.stderr).apply(); // or add java.logging module to runtime image

private static boolean javaUtilLoggingAvailable() {
  try { Class.forName("java.util.logging.Logger"); return true; }
  catch (ClassNotFoundException e) { return false; }
}

try {
  config.handlers(Handlers.javaUtil).apply();
} catch (IllegalStateException e) {
  if (e.getMessage().contains("Could not find java.util.logging")) {
    config.handlers(Handlers.stderr).apply();
  } else throw e;
}

When it happens

Trigger: Using Handlers.javaUtil (log.handlers containing javaUtil) in a constrained JVM where java.util.logging classes fail to load, or where the handler construction throws (e.g. NoClassDefFoundError-style Exception in stripped JREs).

Common situations: Running on a stripped/minimal JRE image without java.util.logging module; unusual classloader setups (old app servers) that block java.util.logging; extremely rare genuine ClassNotFound situations.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

• Could not find SLF4J in your classpath
• Bad serialized file:
• Called remove() before any elements returned
• Cannot initialize logger!
• Cannot initialize logger!

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/c08fd9d2561ee2e6. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/util/logging/RedwoodConfiguration.java:249

      try {
        OutputHandler handler = MetaClass.create("edu.stanford.nlp.util.logging.SLF4JHandler").createInstance();
        handler.leftMargin = config.channelWidth;
        root.addChild(handler);
      } catch (Exception e) {
        throw new IllegalStateException("Could not find SLF4J in your classpath", e);
      }
    };

    /**
     * Output to java.util.Logging. This is a leaf node.
     */
    public static final Thunk javaUtil = (config, root) -> {
      try {
        OutputHandler handler = new JavaUtilLoggingHandler();
        handler.leftMargin = config.channelWidth;
        root.addChild(handler);
      } catch (Exception e) {
        throw new IllegalStateException("Could not find java.util.logging in your classpath", e);
      }
    };

    /**
     * Output to the default location specified by the output() method.
     * Consider using this rather than stderr or stdout.
     */
    public static final Thunk output = (config, root) -> {
      config.outputHandler.leftMargin = config.channelWidth;
      root.addChild(config.outputHandler);
    };

    //
    // Filters
    //
    /**
     * Hide the debug channel only.
     */

View on GitHub (pinned to 1b7edd19c4)