java - How to add an integer element to ArrayList of wildcards in Generics? -

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i have arraylist generic wildcards type, taking number extends. trying add integer values arraylist.

buts it's giving me error saying that

arraylist<? extends number> numberlist = new arraylist<number>();     numberlist = new arraylist<integer>();     numberlist.add(100);

the method add(int, capture#2-of ?) in type arraylist<capture#2-of ?> not applicable arguments (int).

i have tried way also, giving me same error

arraylist<?> numberlist = new arraylist<number>();     numberlist = new arraylist<integer>();     numberlist.add(100);

the error :

the method add(int, capture#2-of ?) in type arraylist<capture#2-of ?> not applicable arguments (int)

you can't. ? extends part tells compiler: of type, don't know, extends number.

so compiler can't guarantee type of whatever want add compatible unknown type. therefor can't add such collection.


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