Multiple Inheritance in Java:

Java does not provide an explicit way to implement multiple-inheritance i.e. a class can never extend multiple classes. But, this can be achieved (simulated) using interfaces. This is possible because of two reasons:

·         A class can implement multiple interfaces

·         A class can simultaneously extend a class and implement one or more interfaces

The forms of the above two are shown below:

1.     interface  A {  ….  }         interface  B {  .…  }         class C implements A, B             { …. }

2.     class  A {  ….  }         interface  B {  .…  }         class C extends A implements B          { …. }

The following program illustrates how interfaces can be used to simulate multiple inheritance. The program has an interface named Allowance and a class named Employee. The class named EmpSal extends Employee and implements Allowance. Thus bringing an effect that the class takes multiple inheritance.

interface Allowance

{

    int DA = 2000;

    int HRA = 3000;

}

class Employee

{

   private int empno;

   private String ename;

 

 public void getdata(int eno,String n)

   {

      empno=eno;

      ename=n;

   }

   public void show()

   {

      System.out.println("Empno:" +empno);

      System.out.println("EName:" +ename);

   }

}

class EmpSal extends Employee implements Allowance

{

   private double sal;

  

   public void getdata(int eno,String n, double s)

   {

      super.getdata(eno,n);

      sal=s;

   }

   public void totalsalary()

   {

      super.show();

      System.out.println("Total Sal:" + (sal+DA+HRA));

   }

}

class Test

{

   public static void main(String as[])

   {

       EmpSal e1=new EmpSal();

       e1.getdata(7369,"Ravi",12000);

       e1.totalsalary();       

   }

}

Output:

Empno: 7369

                EName: Ravi

Total sal:17000