stanfordnlp/CoreNLP · error · IllegalStateException

Something went very very wrong.

Error message

Something went very very wrong.

What it means

Trilean.toBoolean(Boolean valueForUnknown) throws IllegalStateException when the internal value field holds an integer outside {0,1,2}. Since all constructors confine value to those three states, reaching the default branch means internal corruption — hence 'very very wrong'.

Solutions

1. Do not construct Trilean via reflection or raw deserialization across versions; use fromString/TRUE/FALSE/UNKNOWN.
2. Catch IllegalStateException as an unrecoverable bug and fail fast.
3. Recreate the Trilean from a known representation instead of trusting the corrupted one.

try {
  boolean b = t.toBoolean(Boolean.FALSE);
} catch (IllegalStateException e) {
  t = Trilean.fromString(t.toString()); // or rebuild; this is an internal bug
}

When it happens

Trigger: Calling toBoolean on a Trilean whose internal value was corrupted via reflection or deserialization of an object built by a different (incompatible) class version.

Common situations: Java serialization of Trilean across library versions where the state encoding changed; tests tampering with the private field via reflection.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• adjustFinalToken: Unexpected final char: |
• Cannot parse Trilean from string: " + value
• Coordination node must have at least 2 children.
• edge cliqueFeatures[n]=
• Either logic is broken or Gabor can't code.

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/deed570da2b4d68c. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/util/Trilean.java:90

  public boolean isUnknown() {
    return value == 2;
  }

  /**
   * Convert this Trilean to a boolean, with a specified default value if the truth value is unknown.
   * @param valueForUnknown The default value to use if the value of this Trilean is unknown.
   * @return The boolean value of this Trilean.
   */
  public boolean toBoolean(boolean valueForUnknown) {
    switch (value) {
      case 1:
        return true;
      case 0:
        return false;
      case 2:
        return valueForUnknown;
      default:
        throw new IllegalStateException("Something went very very wrong.");
    }
  }

  /**
   * Convert this Trilean to a Boolean, or null if the value is not known.
   * @return Either True, False, or null.
   */
  public Boolean toBooleanOrNull() {
    switch (value) {
      case 1:
        return true;
      case 0:
        return false;
      case 2:
        return null;
      default:
        throw new IllegalStateException("Something went very very wrong.");
    }

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