Home Is List<Dog> a subclass of List<Animal>? Why are Java generics not implicitly polymorphic?
 I'm a bit confused about how Java generics handle inheritance / polymorphism. Assume the following hierarchy - Animal (Parent) Dog - Cat (Children) So suppose I have a method doSomething(List animals). By all the rules of inheritance and polymorphism, I would assume that a List is a List and a List is a List - and so either one could be passed to this method. Not so. If I want to achieve this behavior, I have to explicitly tell the method to accept a list of any subset of Animal by saying doSomething(List animals). I understand that this is Java's behavior. My question is why? Why is polymorphism generally implicit, but when it comes to generics it must be specified?