Slide 8.3: Wrapper class (cont.)

Slide 8.2: Wrapper class
Slide 8.4: Number class
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Wrapper Class (Cont.)

Creating Wrapper Objects
To create a wrapper object, use the wrapper class instead of the primitive type. Since you are now working with objects, you can use certain methods to get information about the specific object. For example, the following methods are used to get the primitive value associated with the corresponding wrapper object:

intValue(), which returns the value of this integer as an int,

byteValue(), which converts the given Integer into a byte after a narrowing primitive conversion and returns it,

shortValue(), which returns the value of this Integer in the short type,

longValue(), which returns the value of this Long as a long,

floatValue(), which returns the float value of this Float object,

doubleValue(), which converts the value of the given Integer to a double type after a widening primitive conversion and returns it,

charValue(), which converts the Character object into its primitive data type char, and

booleanValue(), which returns the value of this Boolean object as a boolean primitive.

Another useful method is the toString() method, which is used to convert wrapper objects to strings.

Wrapper.java (a wrapper example)

public class Wrapper {
  public static void main( String[ ] args ) {
    Integer myInt = Integer.parseInt( args[0] );
    System.out.print( myInt.intValue( ) + " " );
    System.out.print( myInt + " " );
    String myString = myInt.toString( );
    System.out.print( myString + args[0] );
  }
}

shell> java Wrapper ⇒ Output:

Result:

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Slide 8.4: Number class
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“Yesterday I was clever, so I wanted to change the world.
Today I am wise, so I am changing myself.”
― Rumi