Invoke default methods in dynamic proxies automatically

[sbrannen]

Overview

See #28491 for background information.

In JDK dynamic proxies created by Spring AOP, we could potentially introduce support for automatically invoking default methods (or make it easier via a utility).

Available Java APIs

• java.lang.reflect.Method.isDefault()
• java.lang.reflect.InvocationHandler.invokeDefault(Object, Method, Object...)

[injae-kim]

In JDK dynamic proxies created by Spring AOP, we could potentially introduce support for automatically invoking default methods
(or make it easier via a utility).

We can add some class to support automatically invoking default method,
but I found that only 2 proxies (HttpServiceProxyFactory, RSocketServiceProxyFactory) invoke default method now 😄

So I think introducing some utility to invoke default method is enough for now!
We can easily improve it later.

I created simple PR #32018 🙇
If my PR is not what you think, please close it or share your idea~! thank you!