Notifier.java

public interface Notifier {
    void alertWeatherConditions(String weatherConditions);
}

public class Email implements Notifier {
    @Override
    public void alertWeatherConditions(String weatherConditions) {
        if (weatherConditions == "sunny");
            System.out.print("It is sunny");
    }
}

public class Mobile implements Notifier {
    @Override
    public void alertWeatherConditions(String weatherConditions) {
        if (weatherConditions == "rainy")
            System.out.print("It is rainy");
    }
}