ArrayList question

[rotaryfreak]

Hi all,

Is it possible to create an ArrayList which will accept any object from the number class? i have tried something like:

ArrayList<? extends Number> userList = new ArrayList<? extends Numer>();

i get this as error: Cannot instantiate the type ArrayList<? extends Number>

and this doesn't work either:

ArrayList<T> userList = new ArrayList<T>();

and the error here is that T can not be initiated as a type.

I know that by accepting an object of any type will cause exceptions to be thrown like trying to perform numerical operations on string objects, for example, so i need to take that into consideration. again, the question here is: is there any way to initialize an ArrayList that will accept any type from the Number class in java to perform numerical calculations on?

thanks

[JosAH]

It's a bit tricky but very well explained in the first half of this link. That wildcard extension mechanism baffles me too now and then.

kind regards,

Jos

[rotaryfreak]

Thank you Jos, your help is greatly appreciated!