{"id":"63fc519d31fdc96d","repo":"spring-projects/spring-framework","slug":"invalid-method-signature-signature-expected-63fc51","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":"error","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/e8729d043887bf0d0baf91e062e909b56eb2b708/spring-beans/src/main/java/org/springframework/beans/BeanUtils.java#L444-L480","documentation":"Thrown as IllegalArgumentException by resolveSignature when the supplied signature string contains a ')' but no preceding '(', i.e. a stray closing parenthesis with no opening one (BeanUtils.java:461-464). Like error 156 this is a pure parse failure before method lookup.","triggerScenarios":"resolveSignature('foo)', clazz) or 'methodName String)' — a closing paren appears before/without an opening paren.","commonSituations":"Mis-edited config string, bad concatenation, accidental parenthesis from neighboring tokens, or OCR/import of method names that dropped the '(' .","solutions":["Correct the signature to use matched parentheses, or remove parentheses to use minimal-arg lookup.","Validate signature shape at load time: indexOf('(') must be < indexOf(')') and both present together, or neither present.","Centralize signature-building in a helper that always emits balanced parentheses.","Add a test fixture covering known-good signatures."],"exampleFix":"// before\nresolveSignature(\"handle)\", clazz); // ')' without '('\n\n// after\nresolveSignature(\"handle(String)\", clazz);","handlingStrategy":"validation","validationCode":"int open = signature.indexOf('('), close = signature.indexOf(')');\nif (open == -1 && close > -1) {\n  throw new IllegalArgumentException(\"Malformed signature, missing '(': \" + signature);\n}","typeGuard":"public static boolean isBalancedSignature(String s) {\n  int o = s.indexOf('('), c = s.indexOf(')');\n  return (o == -1 && c == -1) || (o > -1 && c > o);\n}","tryCatchPattern":"try { BeanUtils.resolveSignature(sig, clazz); }\ncatch (IllegalArgumentException e) { /* fix the signature string */ }","preventionTips":["Centralize signature building in a helper that emits balanced parentheses.","Validate signature shape before resolving.","Reject stray ')' characters in config-derived method names."],"tags":["spring-beans","beanutils","method-signature","parsing","config"],"analyzedSha":"e8729d043887bf0d0baf91e062e909b56eb2b708","analyzedAt":"2026-08-04T19:07:39.725Z","schemaVersion":2}