18. Concrete class

• A class that inherits the abstract Product class

  
      public class Book extends Product
      {
          private String author;
  
          // regular constructor and methods for the Book class
  
          // implement the abstract method
          @Override
          public String getDisplayText() 
          {
              return super.toString() +
                  "Author:      " + author + "\n";
          }
      }//class Book