Abstract Class vs InterfaceThe following classes are modifications of those in Example 13....

Abstract Class vs Interface

The following classes are modifications of those in Example 13.4. Here, Playable is an abstract class rather than an interface,

   public abstract class Playable   {     public abstract void play();   }

and CD, DVD, and MP3 each extends, rather than implements, Playable.

   public class CD extends Playable   {        // methods for CD   }   public class DVD extends Playable   {        // methods for DVD   }   public class MP3 extends Playable   {        // methods for MP3   }

a. Explain the advantages of designing Playable as an interface rather than as an abstract class.

b. Describe a different example where an interface is clearly preferable to an abstract class.