479: Mainline

Before you can do anything with the FileInputStream classes, you must inform Java that you wish to use classes defined in a group of classes called the input–output package, also known as the java.io package.

In general, if you want to use a particular class in a particular package, then you inform Java that you want that class by including an import statement, such as the following, in your class definition:

         *-- Include a class from the i/o package 
         | 
         |       *-- Include the FileInputStream class 
         v       v 
       ------- --------------- 
import java.io.FileInputStream; 

Alternatively, if you want to tell Java to be prepared to use any class in a particular package, then you include an asterisk, instead of a class name, in the import statement:

         *-- Include a class from the i/o package 
         | 
         |     *-- Include all classes in the package 
         v     | 
       ------- v  
import java.io.*; 

The advantage of using an asterisk is that you can cover all the classes from a single package in one statement; the disadvantage is that your compiler may do its work more slowly.