What’s the meaning of ‘the reflection system’ in UE 4?
Well, in short, it is there to make your life easier, so that you don’t have to face the ‘raw’ C++ all that often.
Reflection is a way for code to interrogate other code for its functionality/parameters. Its used for instance when you want to do an editor interface, because you can ask an instance of a class what that class implements via the “reflection” of its interface. Basically it is a way for code to request that another bit of code calls back to the caller with its information.
So class A has a pointer to B, but doesn’t know what type of thing B is. It calls a function on B saying “hey, tell me what you are” and B responds with “I am a B”, then A can ask “What functions do you have B?” and B can respond with “I have THESE functions”. The point is that both A and B only need to know the reflection interface exists on both and they can work together without knowing anything about the internals of the other class. Which is super useful!
Hope that helps.
This might be useful to read too.