Wrapper classes in java

For every last basic information sort there exist a pre-characterized class, Such predefined class is known as wrapper class. The reason for wrapper class is to change over numeric string information into numerical or major information.

Why use wrapper classes ?

We realize that in java at whatever point we get information structure client, it is through string esteem so here we have to change over these string values in various distinctive datatype (numerical or principal information), for this transformation we utilize wrapper classes.

Example of wrapper class

class WraperDemo
public static void main(String[] args)
String  s[] = {"10", "20"};
System.out.println("Sum before:"+ s[0] + s[1]); // 1020
int x=Integer.parseInt(s[0]); // convert String to Integer
int y=Integer.parseInt(s[1]); // convert String to Integer
int z=x+y;
System.out.println("sum after: "+z); // 30



Sum before: 1020
Sum after: 30

Clarification: In the above illustration 10 and 20 are store in String cluster and next we change over these qualities in Integer utilizing “int x=Integer.parseInt(s[0]);” and “int y=Integer.parseInt(s[1]);” articulation

In “System.out.println(“Sum before:”+ s[0] + s[1]);” Statement ordinarily include two string and yield is 1020 on the grounds that these are String numeric sort not number.

Changing over String information into basic or numerical

We realize that each order line contention of java project is accessible in the fundamental() strategy as cluster of object of string class on String information, one can not perform numerical operation. To perform numerical operation it is profoundly alluring to change over numeric String into principal numeric worth.


“10”  –> numeric String –> only numeric string convert into numeric type or value.
“10x” –> alpha-numeric type –> this is not conversion.
“ABC” –> non-numeric String no conversion.
“A”   –> char String no conversion.