What is concept of Boxing and Unboxing ?

Boxing and unboxing act like bridges between value type and reference types. When we convert
value type to a reference type it’s termed as boxing. Unboxing is just vice-versa. When an object
box is cast back to its original value type, the value is copied out of the box and into the
appropriate storage location.
Below is sample code of boxing and unboxing where integer data type are converted in to object
and then vice versa.
int i = 1;
object obj = i; // boxing
int j = (int) obj; // unboxing