Wrapper Class

Java is an object-oriented language and as said everything in java is an object. But what about the primitives? They are sort of left out in the world of objects, that is, they cannot participate in the object activities, such as being returned from a method as an object, and being added to a Collection of objects, etc. . As a solution to this problem, Java allows you to include the primitives in the family of objects by using what are called wrapper classes.

There is a wrapper class for every primitive date type in Java. This class encapsulates a single value for the primitive data type. For instance the wrapper class for int is Integer, for float is Float, and so on. Remember that the primitive name is simply the lowercase name of the wrapper except for char, which maps to Character, and int, which maps to Integer.

The wrapper classes in the Java API serve two primary purposes:

1.  To provide a mechanism to “wrap” primitive values in an object so that the primitives can be included in activities reserved for objects, like as being added to Collections, or returned from a method with an object return value.
2. To provide an assortment of utility functions for primitives. Most of these functions are related to various conversions: converting primitives to and from String objects, and converting primitives and String objects to and from different bases (or radix), such as binary, octal, and hexadecimal.

The wrapper object of a wrapper class can be created in one of two ways: by instantiating the wrapper class with the new operator or by invoking a static method on the wrapper class.