{"record":{"id":"848f45419665ef0c","repo":"spring-projects/spring-framework","slug":"invalid-method-signature-signature-expected-o","errorCode":null,"errorMessage":"Invalid method signature '{signature}': expected opening '(' for args list","messagePattern":"Invalid method signature '(.+?)': expected opening '\\(' for args list","errorType":"exception","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"warning","filePath":"spring-beans/src/main/java/org/springframework/beans/BeanUtils.java","lineNumber":462,"sourceCode":"\t * means the method called {@code methodName} with exactly 0 arguments.\n\t * <p>If no method can be found, then {@code null} is returned.\n\t * @param signature the method signature as String representation\n\t * @param clazz the class to resolve the method signature against\n\t * @return the resolved Method\n\t * @see #findMethod\n\t * @see #findMethodWithMinimalParameters\n\t */\n\tpublic static @Nullable Method resolveSignature(String signature, Class<?> clazz) {\n\t\tAssert.hasText(signature, \"'signature' must not be empty\");\n\t\tAssert.notNull(clazz, \"Class must not be null\");\n\t\tint startParen = signature.indexOf('(');\n\t\tint endParen = signature.indexOf(')');\n\t\tif (startParen > -1 && endParen == -1) {\n\t\t\tthrow new IllegalArgumentException(\"Invalid method signature '\" + signature +\n\t\t\t\t\t\"': expected closing ')' for args list\");\n\t\t}\n\t\telse if (startParen == -1 && endParen > -1) {\n\t\t\tthrow new IllegalArgumentException(\"Invalid method signature '\" + signature +\n\t\t\t\t\t\"': expected opening '(' for args list\");\n\t\t}\n\t\telse if (startParen == -1) {\n\t\t\treturn findMethodWithMinimalParameters(clazz, signature);\n\t\t}\n\t\telse {\n\t\t\tString methodName = signature.substring(0, startParen);\n\t\t\tString[] parameterTypeNames =\n\t\t\t\t\tStringUtils.commaDelimitedListToStringArray(signature.substring(startParen + 1, endParen));\n\t\t\tClass<?>[] parameterTypes = new Class<?>[parameterTypeNames.length];\n\t\t\tfor (int i = 0; i < parameterTypeNames.length; i++) {\n\t\t\t\tString parameterTypeName = parameterTypeNames[i].trim();\n\t\t\t\ttry {\n\t\t\t\t\tparameterTypes[i] = ClassUtils.forName(parameterTypeName, clazz.getClassLoader());\n\t\t\t\t}\n\t\t\t\tcatch (Throwable ex) {\n\t\t\t\t\tthrow new IllegalArgumentException(\"Invalid method signature: unable to resolve type [\" +\n\t\t\t\t\t\t\tparameterTypeName + \"] for argument \" + i + \". Root cause: \" + ex);","sourceCodeStart":444,"sourceCodeEnd":480,"githubUrl":"https://github.com/spring-projects/spring-framework/blob/69bf83ad716d0cfc4b0520a19b4d8b24c79d1538/spring-beans/src/main/java/org/springframework/beans/BeanUtils.java#L444-L480","documentation":"Thrown as IllegalArgumentException by resolveSignature at BeanUtils.java:462 when the signature string contains a closing ')' but no opening '('. The parser pairs '(' and ')'; a ')' with no '(' is structurally invalid and rejected with a precise hint.","triggerScenarios":"Calling BeanUtils.resolveSignature(\"doStuff)\", clazz) or any signature with a stray ')' and no '('. Typical when a signature is malformed by string slicing or a typo in configuration.","commonSituations":"Mis-edited XML/annotation method expressions; generated code that injects a suffix ')'; YAML/properties value corruption; user-typed method signatures in admin tooling.","solutions":["Add the matching opening '(' so the signature is well-formed, e.g. \"doStuff()\".","If you intended name-only lookup, drop the ')' entirely: \"doStuff\".","Sanity-check the signature: it must have both '(' and ')' or neither."],"exampleFix":"// before\nMethod m = BeanUtils.resolveSignature(\"doStuff)\", clazz);\n\n// after\nMethod m = BeanUtils.resolveSignature(\"doStuff()\", clazz);","handlingStrategy":"validation","validationCode":"int open = signature.indexOf('('), close = signature.indexOf(')');\nboolean ok = (open == -1 && close == -1) || (open > -1 && close > open);\nif (ok) BeanUtils.resolveSignature(signature, clazz);","typeGuard":"static boolean wellFormedSignature(String s) {\n    int o = s.indexOf('('), c = s.indexOf(')');\n    return (o == -1 && c == -1) || (o > -1 && c > o);\n}","tryCatchPattern":"try {\n    BeanUtils.resolveSignature(sig, clazz);\n} catch (IllegalArgumentException ex) {\n    if (ex.getMessage().contains(\"opening '('\")) {\n        sig = sig.replace(\")\", \"()\"); // or fix the source\n    } else throw ex;\n}","preventionTips":["Ensure every ')' has a matching '(' in signature strings.","Drop stray parentheses for name-only lookups.","Sanity-check signatures for balanced parentheses before resolving.","Treat signature strings as data and validate them at config load time."],"tags":["spring-beans","beanutils","method-resolution","signature","parsing","validation"],"backgroundTag":null,"analyzedSha":"69bf83ad716d0cfc4b0520a19b4d8b24c79d1538","analyzedAt":"2026-08-09T15:32:58.770Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}