Wrapper Class - II

Autoboxing

Autoboxing is a process when primitive data types in Java automatically converts into its corresponding wrapper class object. Like, converting an char to Character, int to an Integer or double to a Double.

Autoboxing Example :

import java.util.*;

class Autoboxing

    {

        public static void main(String args[])

            {

                Integer num=5; //Invoke Integer.valueOf()

                Double D=5.4; //Invoke Double.valueOf()

                Float F=5.0F; //Invoke Float.valueOf()

                Character ch='x'; //Character.valueOf()

                ArrayList N= new ArrayList();

                System.out.println("Integer : "+num);

                System.out.println("Double : "+D);

                System.out.println("Float : "+F);

                System.out.println("Character : "+ch);

                N.add(5);

                N.add(9);

                N.add(11);

                N.add(6);

                N.add(7);

              System.out.print("\nArrayList : ");
              System.out.print("\nArrayList : ");
                for(int i=0;i<5;i++)
                    {
                        System.out.print(N.get(i)+"  ");
                    }
            }
    }
            }
            }
    }              

Unboxing

When automatic conversion taken place for an object of a wrN.add(7)apper type to its corresponding primitive value is known as unboxing.

Unboxing Example :

public class Unboxing

    {

        public static void main(String args[])

            {

                Integer NUM=10;

                Double D=12.5;

                int num=NUM;

                double d=D;

                System.out.println("Integer : "+NUM+"  int : "+num);

                System.out.println("Double : "+D+"  double : "+d);

            }

    }