perbezaan antara abstract class dan interface class dalam java

abstract Classes	Interfaces
abstract class can extend only one class or one abstract class at a time	interface can extend any number of interfaces at a time
abstract  class  can extend from a class or from an abstract class	interface can extend only from an interface
abstract  class  can  have  both  abstract and concrete methods	interface can  have only abstract methods
A class can extend only one abstract class	A class can implement any number of interfaces
In abstract class keyword ‘abstract’ is mandatory to declare a method as an abstract	In an interface keyword ‘abstract’ is optional to declare a method as an abstract
abstract  class can have  protected , public and public abstract methods	Interface can have only public abstract methods i.e. by default
abstract class can have  static, final  or static final  variable with any access specifier	interface  can  have only static final (constant) variable i.e. by default

http://beginnersbook.com/2013/05/abstract-class-vs-interface-in-java/