Index 5 out of bounds for length 5 when trying to add an element to an array of objects [duplicate]

Question

public static Groceries [] addGrocery(Groceries[] arr, String name, int price) {
        int arrayLength = Array.getLength(arr);
        System.out.println(arrayLength);
        Groceries[] newGrocery = new Groceries[arrayLength + 1];
        int arrayLength2 = Array.getLength(newGrocery);
        System.out.println(arrayLength2);
        int i;
        for(i = 0; i < arrayLength; i++) {
            newGrocery[i] = arr[i];
            System.out.println("New item added" + i);
        }
        newGrocery[i+1] = new Groceries(name, price);
        return newGrocery;

    }

I have this method where I input an array containing 4 objects and it creates a new array of objects copying the previous 4 objects and then adding one more to the array. But I keep getting this exception.

Answer 1

The exception occurred because you're trying to add an element to an array index (i+1) that just doesn't exist, here:

newGrocery[i+1] = new Groceries(name, price);

Its because i has already been incremented by the for loop at the end to the last index value in the array, by doing i+1 you're trying to access the index = arrayLength2 which doesn't exist.

May be what you want is a List that is capable of expanding its size when a new element is added, unlike array which has a fixed size.