json-path/JsonPath · error · InvalidPathException

Failed to parse token in ArrayIndexOperation:

Error message

Failed to parse token in ArrayIndexOperation: 

What it means

After character validation, ArrayIndexOperation.parse() splits the bracket content on commas and parses each token with Integer.parseInt via parseInteger(). A non-integer token (empty string, out-of-int-range number, stray spaces-only token like '1,,2' producing an empty token) raises InvalidPathException('Failed to parse token in ArrayIndexOperation: <token>').

Source

Thrown at json-path/src/main/java/com/jayway/jsonpath/internal/path/ArrayIndexOperation.java:63

            if (!isDigit(c) && c != ',' && c != ' ' && c != '-') {
                throw new InvalidPathException("Failed to parse ArrayIndexOperation: " + operation);
            }
        }
        String[] tokens = COMMA.split(operation, -1);

        List<Integer> tempIndexes = new ArrayList<Integer>(tokens.length);
        for (String token : tokens) {
            tempIndexes.add(parseInteger(token));
        }

        return new ArrayIndexOperation(tempIndexes);
    }

    private static Integer parseInteger(String token) {
        try {
            return Integer.parseInt(token);
        } catch (Exception e){
            throw new InvalidPathException("Failed to parse token in ArrayIndexOperation: " + token, e);
        }
    }
}

View on GitHub (pinned to 62a4c9f0f6)

Solutions

1. Remove double/leading/trailing commas from the bracket operation.
2. Keep each index within the 32-bit int range and within the array bounds.
3. Validate tokens with a regex like ^-?\\d+(\\s*,\\s*-?\\d+)*$ before building the path.
4. Catch InvalidPathException and log the offending token to locate the malformed segment.

Example fix

// before
JsonPath.read(json, "$.items[1,,2]"); // empty token
// after
JsonPath.read(json, "$.items[1,2]");

if (!operation.trim().matches("-?\\d+(\\s*,\\s*-?\\d+)*")) throw new InvalidPathException("Bad index list: " + operation);

try {
    JsonPath.compile(path);
} catch (InvalidPathException e) {
    if (e.getMessage().startsWith("Failed to parse token in ArrayIndexOperation")) { /* fix token: empty or overflow */ }
    throw e;
}

When it happens

Trigger: Bracket operations like [1,,2] (double comma → empty token), [ 999999999999 ] (overflow beyond int), or [,1] (leading comma) passed to JsonPath.read()/compile().

Common situations: Programmatically generated index lists joined with commas where an empty entry slips in, very large indices copied from other systems, or hand-edited paths with typos.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Failed to parse ArrayIndexOperation:
• Path must start with '$' or '@'
• Path must not end with a '.
• Character '.' on position is not valid.
• Use bracket notion ['my prop'] if your property contains bla

AI-assisted analysis of json-path/JsonPath@62a4c9f0f6 (2026-09-11). Data as JSON: /api/errors/64fa375ad221ea45. Report an issue: GitHub.