Multiple inheritence with interface

[Raj chiru]

Hi...

interface A {
          void add();
     } 

interface B {
          int  add();
     }

class Test implements A,B { }

In preceding code how to provide implementation of add() in Test class

[Seetharaman Venkatasamy]

raj chiru wrote:
In preceding code how to provide implementation of add() in Test class

implementation is nothing but writting the logic(coding) for a method

example

   

public void add(){ 
   System.out.println("raj chiru");
}

public int add(){
  return 42;
}


 

[Eric Mission]

simple, you can't so, you don't. That isn't an issue when following the javabean convention...

interface A {

   void setAdded(int value);
   int getAdded();

}

[Campbell Ritchie]

You have a collision. Collisions between interface methods can always be resolved providing the following three conditions apply:

1: The methods have the same signature. (Otherwise it is overloading and not a collision at all).

2: The methods have compatible intent (see below).

3: The methods have the same return type. (You will have to check in the Java Language Specification for the exact details.)

You are violating no 3 here, and it will never compile.
This is overloading

public interface DoubleArithmetic
{
  void add(double d);
  void subtract(double d);
  void multiply(double d);
  void divide(double d);
}

public interface IntegerArithmetic
{
  void add(int i);
  void subtract(int i);
  void multiply(int id);
  void divide(int i);
}

And this is incompatible intent

public interface Arithmetic
{
  /**
   * Increases the value stored by adding this number to it, eg 1 + 2 = 3
   *@param i The number to add
   */
  void add(int i);
  void subtract(int i);
  void multiply(int i);
  void divide(int i);
}

public interface WackyArithmetic
{
  /**
   * Adds the number passed to make a new number by appending the digits
   * after the existing, eg 2 + 2 = 22, 12 + 34 = 1234.
   *@param i the number to append
   */
  void add(int i);
  void subtract(int i);
  void multiply(int i);
  void divide(int i);
}

Obviously the WackyArithmetic#add method is only suitable for jokes, but I challenge you to implement both those interfaces in accordance with their specifications given.

Have a look at these three add methods: note that the first is intentionally given a vague specification so both sub-interfaces can implement it differently, but still be compatible in intent. 1 2 3