You can never instantiate an interface in java. You can, however, refer to an object that implements an interface by the type of the interface. For example,
public interface A
{
}
public class B implements A
{
}
public static void main(String[] args)
{
A test = new B();
//A test = new A(); // wont compile
}
What you did above was create an Anonymous class that implements the interface. You are creating an Anonymous object, not an object of type interface Test.