Android™ How to Program, Second Edition

GradeBookTest Class That Demonstrates Class GradeBook

Class GradeBookTest (Fig. B.6) creates one object of class GradeBook and demonstrates its methods. Line 14 creates a GradeBook object and assigns it to local variable myGradeBook of type GradeBook. Lines 17–18 display the initial course name calling the object’s getCourseName method. The first line of the output shows the name “null.” Unlike local variables, which are not automatically initialized, every field has a default initial value—a value provided by Java when you do not specify the field’s initial value. Thus, fields are not required to be explicitly initialized before they’re used in a program—unless they must be initialized to values other than their default values. The default value ...