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Java Interface example

  1. /*
  2. Java Interface example.
  3. This Java Interface example describes how interface is defined and 
  4. being used in Java language.
  5.  
  6. Syntax of defining java interface is,
  7. <modifier> interface <interface-name>{
  8.   //members and methods()
  9. }
  10. */
  11.  
  12. //declare an interface
  13. interface IntExample{
  14.  
  15.   /*
  16.   Syntax to declare method in java interface is,
  17.   <modifier> <return-type> methodName(<optional-parameters>);
  18.   IMPORTANT : Methods declared in the interface are implicitly public and abstract.
  19.   */
  20.  
  21.   public void sayHello();
  22.   }
  23. }
  24. /*
  25. Classes are extended while interfaces are implemented.
  26. To implement an interface use implements keyword.
  27. IMPORTANT : A class can extend only one other class, while it 
  28. can implement n number of interfaces.
  29. */
  30.  
  31. public class JavaInterfaceExample implements IntExample{
  32.   /*
  33.   We have to define the method declared in implemented interface,
  34.   or else we have to declare the implementing class as abstract class.
  35.   */
  36.  
  37.   public void sayHello(){
  38.     System.out.println("Hello Visitor !");
  39.   }
  40.  
  41.   public static void main(String args[]){
  42.     //create object of the class
  43.     JavaInterfaceExample javaInterfaceExample = new JavaInterfaceExample();
  44.     //invoke sayHello(), declared in IntExample interface.
  45.     javaInterfaceExample.sayHello();
  46.   }
  47. }
  48.  
  49. /*
  50. OUTPUT of the above given Java Interface example would be :
  51. Hello Visitor !
  52. */

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Umair saying thx

Submitted by Anonymous on Thu, 03/19/2009 - 07:14.

Well thx for this :)

too many comment

Submitted by Anonymous on Thu, 03/26/2009 - 13:33.

too many comment can't see the program...

it's possible or not

Submitted by Anonymous on Fri, 05/08/2009 - 11:40. 

  1.  
  2. class A implements IntfA
  3. {public 
  4. 	int a;
  5. 	A()
  6. 	{this(10);
  7. 	 }
  8.  
  9.     A(int x)
  10. 	{a=x;
  11. 	 }
  12.  
  13. public String MethodofIntfA()
  14. 	 {String s="mehul";
  15. 	 return s;
  16. 	    }
  17.   public void methodofA()
  18. 	{System.out.println(" Method Of  A " +a);
  19. 	 }
  20.  }
  21.  
  22.  
  23. interface IntfA extends IntfB
  24.  {
  25. 	 //constant can be declare;;;;;;;;;;;;;;;;;;;; how use it's
  26. 	public String MethodofIntfA();
  27. 	//public String MethodofIntfA1();
  28. 	}
  29.  
  30. public interface IntfB
  31.  {//constant can be declare;;;;;;;;;;;;;;;;;;;; how use it's
  32. 	public String MethodofIntfB();
  33. 	//public String MethodofIntfA1();
  34. 	}

is it possible or not

Submitted by Anonymous on Fri, 06/12/2009 - 03:25.

class must implement the method of intfB

hahh??

Submitted by Anonymous on Fri, 06/26/2009 - 08:21.

..wahh..!!! its so hard..

about the interface..................

Submitted by Anonymous on Thu, 07/09/2009 - 13:02. 

  1. class A implements IntfA,IntfB
  2. {
  3. public int a;
  4. A()
  5. {this(10);
  6. }
  7.  
  8. A(int x)
  9. {a=x;
  10. }
  11.  
  12. public String MethodofIntfA()
  13. {
  14.     String s="Method-A";
  15. //    System.out.println(s);
  16.        return s;
  17. }
  18. public void methodofA()
  19. {
  20.     System.out.println(" Method Of A " +a);
  21. }
  22. public String MethodofIntfB()
  23. {
  24. String s2="Method-B";
  25. return s2;
  26. }
  27.  
  28. public static void main(String args[])
  29. {
  30.     A a1=new A();
  31.  
  32.     String s1=new String();
  33.     String s2=new String();
  34.     s1=a1.MethodofIntfA();
  35.     s2=a1.MethodofIntfB();
  36.     a1.methodofA();
  37.     System.out.println("");
  38.     System.out.println("Method -IntfA"+s1);
  39.     System.out.println("");
  40.     System.out.println("Method -IntfB"+s2);
  41.  
  42. }
  43. }
  44.  
  45.  
  46. interface IntfA extends IntfB
  47. {
  48. //constant can be declare;;;;;;;;;;;;;;;;;;;; how use it's
  49. public String MethodofIntfA();
  50. //public String MethodofIntfA1();
  51. }
  52.  
  53. interface IntfB
  54. {//constant can be declare;;;;;;;;;;;;;;;;;;;; how use it's
  55. public String MethodofIntfB();
  56. //public String MethodofIntfA1();
  57. }
  58.  
  59. /*****************/
  60. You will have to implement IntfB interface in the Class A
  61. and i will give you some changes. i hope your query is solved.
  62. /*************************/
  63. output
  64. /**************************/
  65.  
  66. Method Of A 10
  67.  
  68. Method -IntfAMethod-A
  69.  
  70. Method -IntfBMethod-B
  71.  
  72. /**************************/

comments.

Submitted by Anonymous on Sat, 08/08/2009 - 06:07.

those comments r helpful.......

slight modification in ur

Submitted by Anonymous on Thu, 02/11/2010 - 13:24.

slight modification in ur answer

class A no need to implement the interface IntfB because it is already extended by the interface IntfA. So,Class A can get all methods of interface IntfA and IntfB by implementing IntfA itself.

isn't it?


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