Check out example codes for "how to replace an element in array in java". It will help you in understanding the concepts better.

Code Example 1

class array{
  public static void main(String[] args){
    int arr[] = {1,2,3,4};
    System.out.println("Before update" + arr[2]);
    arr[2] = 9;//updating the value
    System.out.println("After update" + arr[2]);
  }
}

/*output:-
Before update3
After update9*/

Code Example 2

list.set(1,"new value");

//example ..

List<String> list = new ArrayList<>();
list.add("one");
list.add("two");
list.add("three");
System.out.println(list); // [one,two,three]
list.set(1,"new");
System.out.println(list); //[one,new,three]

Learn ReactJs, React Native from akashmittal.com