JAVA

sum and array list java

int sum = (list.stream().
        mapToInt(i -> i.intValue()).sum()

Get the SUM of integers in List JAVA

int sum = list.stream().mapToInt(Integer::intValue).sum();

sum of list java

double sum = 0;
for(int i = 0; i < m.size(); i++)
    sum += m.get(i);
return sum;