Here you can find the source of getIntListSum(Collection
public static int getIntListSum(Collection<Integer> c)
//package com.java2s; import java.util.Collection; public class Main { public static int getIntListSum(Collection<Integer> c) { int sum = 0; for (Integer i : c) { sum += i;/* w w w . j a v a2 s. c o m*/ } return sum; } }