java - Get primitive value from Object extends Number? -


this question has answer here:

i trying make class can process subtracting, adding, updating number given type (anything extends number).

public class dynamicnumber<t extends number> {      private t number;      public dynamicnumber(t number) {         this.number = number;     }      public void add(t number) {         this.number += number;     }      public void subtract(t number) {         this.number -= number;     }  }

this won't work , throws following exception:

the operator += undefined argument type(s) (t, t)

this because can't use operator objects, , on primitive values.

my question how can primitive value of given object without knowing it's exact type, knowing extends number?

t extends object, never primitive. can use instanceof , cast object extends number. after - if object represents primitive - can use using auto unboxing or using explicit conversion. there no way around this.


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