SUM VALUES OF A MATRIX JAVA code example

Example 1: how to add up all numbers in an array

var numbers = [10, 20, 30, 40] 
var sum = 0;
for (var i = 0; i < numbers.length; i++) {  sum += numbers[i]}

Example 2: arrays.sum

int sum = Arrays.stream("1 2 3 4".split("\\s+")).mapToInt(Integer::parseInt).sum();