bottom.java

北京大学出版社的

package examples.inheritance;

/** A class used to demonstrate inheritance
  * concepts
  */
public class Bottom extends Middle {
   public Bottom() {
      System.out.println( "Constructing a Bottom "
                          + "class object" );
   }

   /** Test method for the class
     * @param args not used
     */
   public static void main( String[] args ) {
      Bottom x = new Bottom();
   }
}

/** Example top class in a hierarchy
  */
class Top {
   public Top() {
      System.out.println( "Constructing a Top "
                          + "class object" );
   }
}

/** Example middle class in a hierarchy
  */
class Middle extends Top {
   public Middle() {
      System.out.println( "Constructing a Middle "
                          + "class object" );
   }
}