In this blog post, I am going to demonstrate all of Java’s loops. I am going to write loops that prints the sum of numbers in a List.

For Loop

private static int sumFor(List<Integer> numbers) { 
    int sum = 0; 
    for(int i=0; i < numbers.size();i++) { 
        sum += numbers.get(i); 
    } 
    return sum; 
}

For Each Loop

private static int sumForEach(List<Integer> numbers){ 
    int sum = 0; 
    for(int num:numbers){ 
        sum += num; 
    } 
    return sum; 
}

While Loop

private static int sumWhile(List<Integer> numbers){ 
    int sum = 0; 
    int i = 0; 
    while (i < numbers.size()){ 
        sum += numbers.get(i); 
        i++; 
    } 
    return sum; 
}

Do While Loop

private static int sumDoWhile(List<Integer> numbers){ 
    int sum = 0; 
    int i = 0; 
    do { 
        sum += numbers.get(i); 
        i++; 
    } while (i < numbers.size()); 
    return sum; 
}