Using Enum

public enum Grade { A, B, C, D, F, INCOMPLETE };
 
public class Student {
 
 
 
  private String firstName;
 
  private String lastName;
 
  private Grade grade;
 
 
 
  public Student(String firstName, String lastName) {
 
    this.firstName = firstName;
 
    this.lastName = lastName;
 
  }
 
  .....
 
 public void assignGrade(Grade grade) {
 
    this.grade = grade;
 
  }
 
 
 
  public Grade getGrade( ) {
 
    return grade;
 
  }
 
}            
 
 
 
public void testGradeAssignment(PrintStream out) throws IOException {
 
      Student student1 = new Student("Brett", "McLaughlin");
 
      Student student2 = new Student("Ben", "Rochester");
 
      Student student3 = new Student("Dennis", "Erwin");
 
 
 
      student1.assignGrade(Grade.B);
 
      student2.assignGrade(Grade.INCOMPLETE);
      student3.assignGrade(Grade.A);
 
}