All of Java's primitive data types have an associated
Wrapper class. These wrapper classes provide useful
functions such as conversion or comparisons most of which
are used by Java implicitly.

Also a wrapper serves as a container for primitive values in
conditions where a reference type is expected.

These classes are Wrapper classes.We hav them as we cant 
pass an primitive directly through an method to different 
class.So we need wrapper classes to convert them to their 
already defined classes.Send them n again unpack them.