Guys, got a question abut Generics and Up\Down casting.

Question

Guys, got a question abut Generics and Up\Down casting.

List<Object> c = new ArrayList<>();
Cant understand why we CAN do this:
List<? super Number> d = c;
But CANNOT do this:
List<? extends Number> d1 = c;
We have pointed that c is a list of Objects. So why we cant say it is also a List of Integer (which extend Number AND also IS-A Object) ?

0

27.09.2018

2 ответов

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@izhytnii Автор вопроса

:)

0

27.09.2018

Alex · Accepted Answer

Alex

The super example works because number is a child of object

0

27.09.2018

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Guys, got a question abut Generics and Up\Down casting.

2 ответов

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