Check out example codes for "java set value of arraylist". It will help you in understanding the concepts better.

Code Example 1

import java.util.ArrayList;

public class SetExample {
  public static void main(String args[]) {
    ArrayList<Integer> arraylist = new ArrayList<Integer>();
    arraylist.add(1);
    System.out.println(arrayList.get(0));
    //1
	arrayList.set(0, 2)
    System.out.println(arrayList.get(0));
    //2
  }
}

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