Hi Friend,

Differences:

1)An abstract class may contain complete or incomplete methods while Interfaces can contain only the signature of a method but no body.

2)An abstract class cannot support multiple inheritance, while an interface can support multiple inheritance.

3)One class can inherit multiple interface but it can't inherit multiple abstract class

For more information, visit the following link:

http://www.roseindia.net/java/master-java/interface.shtml

Thanks

JAVA have all alternatives :

**1,CLASS- Class have only Concrete Methods. 2,ABSTRACT CLASS- Abstract class have both concrete methods and abstract methods. 3,INTERFACE-Interface have only abstract methods.** if u want any one specification u can use that.