Can we use generic to allow only specific types instead of any type ?

Question

Suppose I have three isolated public classes (no IS-A relationship) A, B and C. I want to define a field in C such that it\'s type can either be A or B.

Currently I\'m a

Answer 1

You can't do that but you can set boundaries on what type you want to accept.

If you have

class A extends BaseType {}
class B extends BaseType {}

you can define the class C to be

class C { ... }

Either a class or an interface as base type work.