abstract class Creator{
    // Definimos método abstracto
    public abstract Product factoryMethod();
}

public class ConcreteCreator extends Creator{
    public Product factoryMethod() {
        return new ConcreteProduct();
    }
}

public interface Product{
    public void operacion();
}

public class ConcreteProduct implements Product{
    public void operacion(){
        System.out.println("Una operación de este producto");
    }
}

public static void main(String args[]){
    Creator aCreator;
    aCreator = new ConcreteCreator();
    Product producto = aCreator.factoryMethod();
    producto.operacion();
}