stanfordnlp/CoreNLP · error · ParseException

generateParseException()

Error message

generateParseException()

What it means

TokenSequenceParser (JavaCC-generated) throws the ParseException produced by generateParseException() when token consumption fails inside jj_3 routines/backtracking. The "message" here is literally "generateParseException()" because the log/throw site stringifies the call; the real detail is in the generated ParseException describing the token choices that failed at the parse position.

Solutions

1. Read the full ParseException (or its getMessage()) for the offending token and expected alternatives
2. Fix the TokensRegex pattern at the indicated position — balance brackets and check escapes
3. Test the pattern in small increments to isolate the failing fragment
4. Verify the pattern syntax against the TokensRegex documentation for your CoreNLP version

Example fix

// before
Env env = TokenSequenceParser.parseNewEnv(p, "[ { word:/a/ } ]"); // unbalanced / bad syntax
// after
Env env = TokenSequenceParser.parseNewEnv(p, "[{word:/a/}]"); // valid TokensRegex syntax

// Java: sanity-check TokensRegex pattern structure before parsing
static boolean looksBalanced(String p) {
  int b = 0, c = 0;
  for (char ch : p.toCharArray()) {
    if (ch == '[') b++; if (ch == ']') b--;
    if (ch == '{') c++; if (ch == '}') c--;
    if (b < 0 || c < 0) return false;
  }
  return b == 0 && c == 0;
}

try {
  Env env = TokenSequenceParser.parseNewEnv(env0, pattern);
} catch (ParseException e) {
  throw new IllegalArgumentException("TokensRegex syntax error at token " + e.currentToken + ": " + pattern, e);
}

When it happens

Trigger: Calling TokensRegex parsing APIs (TokenSequenceParser.compile...) with a pattern string whose syntax doesn't match the grammar at some token — invalid regex constructs, unbalanced brackets/braces, bad relation syntax in a TokensRegex expression.

Common situations: Typos in TokensRegex patterns; using syntax from a different CoreNLP version; unbalanced parentheses/brackets in pattern strings; invalid escape sequences.

Related errors

• Parsing failed. Error:
• 2 arguments expected, got
• Annotation field cannot be null
• : Entry has multiple types for : . Taking type to be
• Attribute already defined:

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/c2ff16eba2e3c523. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/ling/tokensregex/parser/TokenSequenceParser.java:3833

	 else token = token.next = token_source.getNextToken();
	 jj_ntk = -1;
	 if (token.kind == kind) {
	   jj_gen++;
	   if (++jj_gc > 100) {
		 jj_gc = 0;
		 for (int i = 0; i < jj_2_rtns.length; i++) {
		   JJCalls c = jj_2_rtns[i];
		   while (c != null) {
			 if (c.gen < jj_gen) c.first = null;
			 c = c.next;
		   }
		 }
	   }
	   return token;
	 }
	 token = oldToken;
	 jj_kind = kind;
	 throw generateParseException();
  }

  @SuppressWarnings("serial")
  static private final class LookaheadSuccess extends java.lang.Error {
    @Override
    public Throwable fillInStackTrace() {
      return this;
    }
  }
  static private final LookaheadSuccess jj_ls = new LookaheadSuccess();
  private boolean jj_scan_token(int kind) {
	 if (jj_scanpos == jj_lastpos) {
	   jj_la--;
	   if (jj_scanpos.next == null) {
		 jj_lastpos = jj_scanpos = jj_scanpos.next = token_source.getNextToken();
	   } else {
		 jj_lastpos = jj_scanpos = jj_scanpos.next;
	   }

View on GitHub (pinned to 1b7edd19c4)