JAVA EE: Java Tutorial : Java wrapper class(Autoboxing and unboxing)

Monday, 22 February 2016

Java Tutorial : Java wrapper class(Autoboxing and unboxing)

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Java Tutorial : Java wrapper class(Autoboxing and unboxing)

PrimitiveToWrapperExample.java

public class PrimitiveToWrapperExample
{

    public static void main(String[] args)
    {

        /*
         * Primitive to Wrapper Example.
         * 
         * Converting int into Integer
         */

        int intValue = 300;
        Integer integerObj1 = Integer.valueOf(intValue);

        System.out.println("integerObj1 = " + integerObj1);

        /*
         * Autoboxing, now compiler will write
         * Integer.valueOf(a) internally
         */

        Integer integerObj2 = intValue;
        System.out.println("integerObj2 = " + integerObj2);

    }
}

Output

integerObj1 = 300
integerObj2 = 300

WrapperToPrimitiveExample.java

public class WrapperToPrimitiveExample
{

    public static void main(String[] args)
    {
        /*
         * Wrapper to Primitive
         * 
         * Converting Integer to int
         */
        Integer integerObj = new Integer(3);
        System.out.println("integerObj = " + integerObj);

        /*
         * converting Integer to int
         */
        int i = integerObj.intValue();
        System.out.println("i = " + i);

        /*
         * Unboxing, now compiler will write a.intValue()
         * internally
         */
        int j = integerObj;

        System.out.println("j = " + j);

    }

}