pinpoint-apm/pinpoint · warning · IllegalArgumentException

invalid signature :

Error message

invalid signature :

What it means

JavaAssistUtils.byteCodeSignatureToObjectType maps a JVM type signature character (L for objects, [ for arrays, plus primitives) to its Java type. If the leading character at the given index is none of the known signature codes, the signature string is malformed and IllegalArgumentException is thrown.

Source

Thrown at agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/util/JavaAssistUtils.java:326

            case 'F':
                return "float";
            case 'I':
                return "int";
            case 'J':
                return "long";
            case 'S':
                return "short";
            case 'V':
                return "void";
            case 'Z':
                return "boolean";
            case 'L':
                return toObjectType(signature, startIndex + 1);
            case '[': {
                return toArrayType(signature);
            }
        }
        throw new IllegalArgumentException("invalid signature :" + signature);
    }

    private static String toArrayType(String description) {
        final int arraySize = getArraySize(description);
        final String objectType = byteCodeSignatureToObjectType(description, arraySize);
        return arrayType(objectType, arraySize);
    }

    private static String arrayType(String objectType, int arraySize) {
        final int arrayStringLength = ARRAY.length() * arraySize;
        StringBuilder sb = new StringBuilder(objectType.length() + arrayStringLength);
        sb.append(objectType);
        for (int i = 0; i < arraySize; i++) {
            sb.append(ARRAY);
        }
        return sb.toString();
    }

View on GitHub (pinned to 744c3d3075)

Solutions

1. Validate the descriptor format before calling (must start with '(', contain valid JVM type codes)
2. Convert Java names to JVM descriptors first (e.g. javaNameToJvmName/toDescriptor) rather than passing raw Java names
3. Check for truncation/corruption where the signature string is produced
4. Log the full signature and position to locate the offending character

Example fix

// before
JavaAssistUtils.objectType("java.lang.String"); // not a descriptor -> throws
// after
JavaAssistUtils.objectType("Ljava/lang/String;"); // valid JVM signature

String ok = "BCDFIJSZL["; if (signature == null || signature.isEmpty() || ok.indexOf(signature.charAt(0)) < 0) { throw new IllegalArgumentException("bad signature: " + signature); }

try { type = JavaAssistUtils.objectType(sig); } catch (IllegalArgumentException e) { logger.warn("Bad signature {}", sig); type = sig; }

When it happens

Trigger: Passing a method/field descriptor whose component type starts with an unrecognized character (not B/C/D/F/I/J/S/Z/L/[/V) at the current parse position; callers include parseParameterSignature and objectType.

Common situations: Hand-crafted or truncated descriptors; passing a Java class name instead of a JVM descriptor; descriptors corrupted by string manipulation or wrong substring offsets.

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.

Related errors

• invalid signature. objectName not found :
• '(' not found. signature:
• ')' not found. signature:
• agentIndex not found:${transactionId}
• invalid transactionId:${transactionId}

AI-assisted analysis of pinpoint-apm/pinpoint@744c3d3075 (2026-09-07). Data as JSON: /api/errors/72ac9f4e7ae82f94. Report an issue: GitHub.