public static int sum(List<Integer> list){
        int sum=0;
        for(Iterator iter=list.iterator();iter.hasNext();){
             int i=((Integer)iter.next()).intValue();
             sum+=i;
        }
        return sum;
    }

------解决方案--------------------
Java code
11. public static int sum(List<Integer> intList){
12.   int sum = 0;
13.   for (int i : intList) {
14.     
15.     sum+=i;
16.   }
17.   return sum;
18. }