Boxing and Unboxing example

01_without_boxing.java

import java.util.ArrayList;

public class Main {
  public static void main(String[] args) {
    ArrayList<Integer> myList = new ArrayList<Integer>();

    myList.add(new Integer(10));
    myList.add(new Integer(11));
    myList.add(new Integer(12));

    int listSum = 0;
    for(Integer val : myList) {
      listSum += val.intValue();
    }
    System.out.println("The sum of list is: " + listSum);
  }
}
// The sum of the list is: 33

02_with_boxing.java

import java.util.ArrayList;

public class Main {
  public static void main(String[] args) {
    ArrayList<Integer> myList = new ArrayList<Integer>();

    myList.add(10);
    myList.add(11);
    myList.add(12);

    int listSum = 0;
    for(int val : myList) {
      listSum += val;
    }
    System.out.println("The sum of list is: " + listSum);
  }
}
// The sum of the list is: 33