How to initialize field with default constructor using annotation

guys! Could you tell me please, how we can to initialize field, using annotation? For example: We have few custom classes: Foo; Bar. And in Main class, we entered two fields

public class Main {
    Foo foo;
    Bar bar;
}

I want to create annotation, which helps to initialize these fields. In final result I want to see something like this:

@Initialize
Foo foo;
@Initialize
Bar bar;