apache/shenyu · error · ShenyuException

args.length < types.length

Error message

args.length < types.length

What it means

ParamCheckUtils.checkParamsLength enforces that the number of supplied arguments matches the expected number of parameter types. If argsLength is less than typesLength it throws ShenyuException 'args.length < types.length', preventing ArrayIndexOutOfBoundsException later when mapping args to types.

Solutions

1. Ensure the caller supplies one argument per declared parameter type before invoking.
2. Validate request payloads on the client side so all required args are present.
3. Check that MetaData parameterTypes and args registered by the backend service are consistent (re-register the service after signature changes).
4. Wrap calls with checkParamsLength defensively and surface a clear client error.

Example fix

// before
Object result = method.invoke(service, new Object[]{arg1}); // 1 arg, 2 types
// after
ParamCheckUtils.checkParamsLength(2, method.getParameterTypes().length);
Object result = method.invoke(service, arg1, arg2);

ParamCheckUtils.checkParamsLength(args.length, method.getParameterTypes().length);

boolean argsMatch = args != null && types != null && args.length >= types.length;

try { invoke(...); } catch (ShenyuException e) { if (e.getMessage().contains("args.length")) { respond 400 "missing arguments"; } }

When it happens

Trigger: Invoking reflection-based calls (e.g. in proxy plugins) with fewer actual arguments than declared parameter types; passing null/empty args array to a method with required parameters.

Common situations: Client metadata (parameterTypes vs args) out of sync after backend API signature change; generic invocations (Dubbo/HTTP proxy) built from MetaData with truncated args; request body missing fields.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• the validation ExistProviderMethod invoked error
• Max response body size must not be negative
• build json response message is error, newBuilder method is…
• can not get defaultInstance Field of
• can not get fullMethodName Field of

AI-assisted analysis of apache/shenyu@567142e072 (2026-09-12). Data as JSON: /api/errors/94a6321d587c8146. Report an issue: GitHub.

Appendix: source

Thrown at shenyu-common/src/main/java/org/apache/shenyu/common/utils/ParamCheckUtils.java:47

    
    /**
     * Body is empty boolean.
     *
     * @param body the body
     * @return the boolean
     */
    public static boolean bodyIsEmpty(final String body) {
        return Objects.isNull(body) || StringUtils.isEmpty(body) || "null".equals(body);
    }

    /**
     * Check params length.
     * @param argsLength params length.
     * @param typesLength types length.
     */
    public static void checkParamsLength(final Integer argsLength, final Integer typesLength) {
        if (argsLength < typesLength) {
            throw new ShenyuException("args.length < types.length");
        }
    }
}

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