MultipleInheritance in Java

interface a
{void display();

}
interface b
{void display1();


}

class aa implements a,b 
{
int a2=10,b2=5;
public void display()
{
System.out.println("Sum of 2 number"+(a2+b2));
}
public void display1()
{System.out.println("product of 2 number"+(a2*b2));
}
}

class multiple 
{
public static void main(String a[])
{
aa a1=new aa();
a1.display();
a1.display1();
}
}