java insert into lists code example

Example 1: java insert array

// ! IMPORTANTE !
// in JAVA an array is not the same as an ArrayList object!!
// 1 - declare, instanciate and populate
int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; 
// 2 - declare and instanciate an int array with maxSize
// note: the index goes between 0 and maxSize-1
int newarr[] = new int[maxSize];
// 2.1 - insert the value n on the position pos
newarr[pos] = n; 
// 2.2 - insert values recursively
for (i = 0; i < maxSize; i++) { newarr[i] = arr[i]; }

Example 2: java insert into arraylist

ArrayList str=new ArrayList();
str.add(0);
str.add(1);
 // Result = [0, 1]
    
str.add(1, 11);
 // Result = [0, 11, 1]

Example 3: ArrayList add(int index, E element) method in java

import java.util.ArrayList;
public class ArrayListAddMethodExample
{
   public static void main(String[] args)
   {
      // creating an empty ArrayList with initial capacity
      ArrayList al = new ArrayList(6);
      al.add(12);
      al.add(14);
      al.add(16);
      al.add(18);
      al.add(20);
      // adding element 15 at fourth position
      al.add(3, 15);
      for(Integer number : al)
      {
         System.out.println("Number: " + number);
      }
   }
}