A Wrapper class is a class whose object wraps or contains a primitive data types. When we create an object to a wrapper class, it contains a field and in this field, we can store a primitive data types.

In other words, we can wrap a primitive value into a wrapper class object.

                   

                 

Need of Wrapper Classes

  1. They convert primitive data types into objects. Objects are needed if we wish to modify the arguments passed into a method (because primitive types are passed by value).
  2. The classes in java.util package handles only objects and hence wrapper classes help in this case
  3. Data structures in the Collection framework, such as ArrayList and Vector, store only objects (reference types) and not primitive
  4. An object is needed to support synchronization in multithreading.

Wrapping & Unwrapping Example