String a Wrapper Class

[Rahul Juneja]

Hi,

It may seem a bit awkward but just wanted to know whether String Class is a wrapper class as it also wraps the characters which are primitive type. Okay can somebody tell me what exactly are wrapper classes ?

Thanks,
Rahul Juneja

[Pradeep bhatt]

wrapper classes wrap primitives. For e.g. Integer wraps int,
Character wraps char. String is a sequnce of characters and does not wrap primitives.

[somkiat puisungnoen]

Java wrappers are classes that wrap up primitive values in classes that offer utility methods to manipulate the values. If for example you want to store a set of int values in the elements of a Vector, the values in a Vector must be objects and not primitives. When you want to retrieve the values wrapped up in the Integers that are in the Vector elements you will need to cast the elements back to Integers and then call the toxxValue in order to get back the original number. The following code demonstrates this technique.

import java.util.*;
public class VecNum{
    public static void main(String argv[]){
    Vector v = new Vector();
    v.add(new Integer(1));
    v.add(new Integer(2));
    for(int i=0; i < v.size();i ++){
        Integer iw =(Integer) v.get(i);
        System.out.println(iw.intValue());
    }
   }
}
 

 

The wrapper classes also offer utility methods for converting to and from the int values they represent. Thus if you have a string that could also represent a number, you can use a wrapper class to perform that calculation.
The methods of the wrapper classes are all static so you can use them without creating an instance of the matching wrapper

[Vicky Jain]

Hi Pradeep,

Thats tha same i was trying to say him yday. Wrapper classer just wrap primitive data types.

Thanks

[Rahul Juneja]

Thanks everybody. I understood ur poimnt guys. Can the Bartender or sheriff Please close this Topic.

Thanks,
Rahul Juneja