Android apps are written in Java. Android beginners assume that Java programming best practices are equally applicable to Android programming. In this paper, we perform a small case study to show that the assumption can be wrong. We port a well-written Java application to Android. A certain key assumption of object-oriented programming doesn't hold on the Android platform. Thus, some of the best practices in writing Java programs are not best practices for Android. In fact, they are anti-patterns that Android programmers should avoid. We show concrete examples of these anti-patterns or watch-outs along with their fixes.