incompatible types object cannot be converted to Number

Question

I am trying to compile the below code but getting "incompatible types object cannot be converted to Number at for(Number n:list).

import java.util.*;

 class Output
  {
    public static double sumOfList(List list)
    {
        double s=0.0;

        for(Number n:list)
            s+=n.doubleValue();

        return s;
    }

    public static void main(String[] args) 
    {
        List li=Arrays.asList(1,2,3);
        System.out.println(SumOfList(li));
    }
  }

@SotiriosDelimanolis I really don't think this counts as a duplicate of that question. This question is simple enough there is probably some duplicate out there, but the one above... — Matt Ball, Jan 17 '15 at 20:09

Matt Ball · Answer 1 · 2015-01-17T18:55:35.823

4

Listen to the "Raw types" warning your compiler outputs and use generics.

Declare the list type as List<Number> or List<? extends Number>.

http://ideone.com/L6mIhA

(and never use raw types. They only exist for backwards compatibility.)

edited Jan 17 '15 at 18:55

answered Jan 17 '15 at 18:50

Matt Ball

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score 1 · Accepted Answer · answered Jan 17 '15 at 18:50

1

chage your code to this:

public static double sumOfList(List<Number> list){
..
}

answered Jan 17 '15 at 18:50

roeygol

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1

thanks i changed in my code so now it work – Shaikh Nadeem Jan 17 '15 at 19:08

incompatible types object cannot be converted to Number

2 Answers2