.class error

Question

Hi,
I am trying to make a simple code where a main program calls a method in a class so that the total sum of all elements of an array is calculated. Here is my code:
public class playingwithArrays
        static void sumArray(int [] arr){
            int sum = 0;
                for(int i = 0; i<arr.length; i++){
                    sum+= arr;
System.out.println ("Total sum of array is" + sum);
This is the class where there is the method i want to access
The class below is the main class:public class Start
public static void main (STring[] args){
int [] arr = new int [10];
for (int i; i<arr.length; i++){
arr[i] = (i+1);
playingwithArrays summation = new playingwithArrays ();
summation.sumArray(int arr[]);
Where there is bold the compiler is giving me a .class error. Please can you help me as I am a beginner and I am trying to learn java!                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

It's a good idea to follow standard conventions about nAmEs. PlayingWithArrays, not playingwithArrays.
You define sumArray() as a static method. That means that it will not be associated with a particular instance of the PlayingWithArrays class. And so you can access it without having to create a new instance of the class.
It's not actually wrong to say summation.sumArray(...), it's just that it looks odd. It would better be PlayingWithArrays.sumArray(...).
The actual error is what you are passing as the argument. This method expects an array of int and that's what you should pass it. You don't need the int and [] business that goes into the declaration of a method, just use the variable.
PlayingWithArrays.sumArray(arr);This will use a static method of the PlayingWithArrays class to print out the sum of the array elements.