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Generics question

Saroja Penn
Greenhorn

Joined: Nov 03, 2007
Posts: 3
An ArrayList<Animal> can accept references of type Dog, Cat, or any other
subtype of Animal (subclass, or if Animal is an interface, implementation).

The above line is from the 2-minute drill of Generics chapter.

Could anyone please explain what this means? I cannot follow what it says. I thought List<Animal> takes only List<Animal>. Please explain with a small example.

Appreciate any help
Thank you.
Kelvin Chenhao Lim
Ranch Hand

Joined: Oct 20, 2007
Posts: 513
It's referring to the elements that you can insert into the list object. You can put any Animal object, including subclass instances, into an List<Animal>.

But you're correct that a List<Animal> reference variable can only be safely assigned a List<Animal> object.


SCJP 5.0
Saroja Penn
Greenhorn

Joined: Nov 03, 2007
Posts: 3
Thank you, Kelvin.

Its clear now.
 
 
subject: Generics question