Currently dubbo support java6, java7 and java8.

All unit test pass in java9, we should consider add official support for java9 and even java10.
Currently travis support java9. java10 is in progress (https://github.com/travis-ci/travis-ci/issues/9368)

As discussed in mail list, the first step is to add java9 in travis ci.
}
            }
            if (finded.isEmpty()) {
                throw new NoSuchMethodException("No such method " + methodName + " in class " + clazz);
            }
            if (finded.size() > 1) {
                String msg = String.format("Not unique method for method name(%s) in class(%s), find %d methods.",
                        methodName, clazz.getName(), finded.size());
                throw new IllegalStateException(msg);
            }
            method = finded.get(0);
        } else {
            Class<?>[] types = new Class<?>[parameterTypes.length];
            for (int i = 0; i < parameterTypes.length; i++) {
                types[i] = ReflectUtils.name2class(parameterTypes[i]);
            }
            method = clazz.getMethod(methodName, types);
        }
        Signature_METHODS_CACHE.put(signature, method);
        return method;
    }
    public static Method findMethodByMethodName(Class<?> clazz, String methodName)
            throws NoSuchMethodException, ClassNotFoundException {
        return findMethodByMethodSignature(clazz, methodName, null);
    }
    public static Constructor<?> findConstructor(Class<?> clazz, Class<?> paramType) throws NoSuchMethodException {
        Constructor<?> targetConstructor;
        try {
            targetConstructor = clazz.getConstructor(new Class<?>[]{paramType});
        } catch (NoSuchMethodException e) {