### Environment

* Dubbo version: 2.7.1
* Operating System version: Mac os
* Java version: 1.8

### Steps to reproduce this issue

1. i see the ClassUtils.getMethodName method source code,

```
public static String getMethodName(Method method, Class<?>[] parameterClasses, String rightCode) {
        if (method.getParameterTypes().length > parameterClasses.length) {
            Class<?>[] types = method.getParameterTypes();
            StringBuilder buf = new StringBuilder(rightCode);
            for (int i = parameterClasses.length; i < types.length; i++) {
                if (buf.length() > 0) {
                    buf.append(",");
                }
                Class<?> type = types[i];
                String def;
                if (type == boolean.class) {
                    def = "false";
                } else if (type == char.class) {
                    def = "\'\\0\'";
                } else if (type == byte.class
                        || type == short.class
                        || type == int.class
                        || type == long.class
                        || type == float.class
                        || type == double.class) {
                    def = "0";
                } else {
                    def = "null";
                }
                buf.append(def);
            }
        }
        return method.getName() + "(" + rightCode + ")";
    }
```
in my opinion, for(...) is to set default values for functions. But in the end, buf not used.
so, maybe should return method.getName() + "(" + buf.toString()  + ")" when for(...) end.


return "0";
        } else if (char.class.equals(type)) {
            return "'\\0'";
        } else if (boolean.class.equals(type)) {
            return "false";
        } else {
            return "null";
        }
    }
    public static <K, V> Map<K, V> toMap(Map.Entry<K, V>[] entries) {
        Map<K, V> map = new HashMap<K, V>();
        if (entries != null && entries.length > 0) {
            for (Map.Entry<K, V> entry : entries) {
                map.put(entry.getKey(), entry.getValue());
            }
        }
        return map;
    }
    /**
     * get simple class name from qualified class name
     */
    public static String getSimpleClassName(String qualifiedName) {
        if (null == qualifiedName) {
            return null;
        }
        int i = qualifiedName.lastIndexOf('.');
        return i < 0 ? qualifiedName : qualifiedName.substring(i + 1);
    }
}