Introductionto "Wrapper" classes, this is a tool or concept provided in theJava Programming Language that gives us a way to utilize nativedatatypes as Objects with attributes and methods.

A Wrapper class inJava is the type of class which contains or the primitive datatypes. When a wrapper class is created a new field is created andin that field, we store the primitive data types. It also providesthe mechanism to covert primitive into object and object intoprimitive.

Working withcollections, we use generally genericArrayList instead of thisArrayList. An integer is wrapper classof int primitive type. We use a Java wrapper class because forgenerics we need objects, not the primitives."Generics' is coveredin Chapter 17, which we will not be able to cover thissemester.

Advantages of Java Wrapper Class

• They are used to convert the primitive data types into objects(Objects are needed when we need to pass an argument in the givenmethod).
• The package java.util contains classes which only handlesobjects, so it helps in this case too.
• Data Structures store only objects and primitive datatypes.
• In multithreading, we need an object to supportsynchronization.

Primitive Data Type	Wrapper Class
byte	Byte
long	Long
float	Float
int	Int

1. Create a WordCounter application, submit WordCounter.java.

Word Counter takesinput of a text file name (have a sample file in the same directoryas your Word Counter application to we don't have to fully path thefile). The output of our Word Counter application is to echo thefile name and the number of words contained within the file.

Consult Code Listing9-9 and 9-10 for examples of analyzing data in a file. Notice theCode listings use Exceptions, we will learn MORE aboutExceptions and Exception Handling in Chapter 11, so stay tuned!