Simple interface example in Java

//  Program to use Simple Interface.

interface  AInterface
{
void showA();
}
class Test  implements  AInterface
{
public void showA()
{
 System.out.println("showA() of A interface.");
}
}
class  InterfaceTest1
{
public static void main( String args[ ] )
{
 Test  t1 = new Test();
 t1.showA();
 
 AInterface  a1 = new Test();
 a1.showA();
 
 a1 = t1;
 a1.showA();
}
}

Output:
showA() of A interface.
showA() of A interface.
showA() of A interface.