how to do sum of elements in java in arraylist code example

Example 1: sum of arraylist java 8

int total = numbers.stream().mapToInt(i -> i.intValue()).sum();
		System.out.print(total);

Example 2: inbuild method to sum of an arraylist elements in java

//If you have a List<Integer>
int sum = list.stream().mapToInt(Integer::intValue).sum();

//If it's an int[]
int sum = IntStream.of(a).sum();