Here you can find the source of sumDouble(List
public static double sumDouble(List<Double> list)
//package com.java2s; //License from project: Open Source License import java.util.List; public class Main { public static double sumDouble(List<Double> list) { double sum = 0; for (Double i : list) { if (i != null) sum += i;/* ww w . j a v a2 s .c o m*/ } return sum; } }