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Thread: keywords

  1. #1
    Junior Member
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    Default keywords

    hi friends,

    can anyone tell me the difference between

    extend and implement

    class implements interface and interface implements interface


  2. #2
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    Default Re: keywords

    Here is a link that you should read. It teaches you everything about OOP. http://download.oracle.com/javase/tutorial/java/concepts/index.html

  3. #3
    Super Moderator helloworld922's Avatar
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    Default Re: keywords

    Extends can be used in two different contexts: an interface extending another interface, or a class extending another class. Implements can only be use in the context of a class implementing an interface. An interface can never extend/implement a class, and a class can never extend an interface. Classes are allowed to implement multiple interfaces but can only extend one class. Interfaces can extend any number of interfaces they want to.

    Syntaxes:

    public class BaseClass
    {}
     
    public interface BaseInterface
    {}
     
    public class ClassA extends BaseClass
    {}
     
    public class ClassB implements BaseInterface
    {}
     
    public interface InterfaceA extends BaseInterface
    {}
     
    public interface InterfaceB
    {}
     
    public class ClassB implements InterfaceA, InterfaceB
    {}
     
    public interface InterfaceC extends InterfaceA, InterfaceB
    {}

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