Empirical Studies of Mobile Apps and Their Dependence on Mobile Platforms

Abstract

Our increasing reliance on mobile devices has given rise to a new class of software applications (i.e., mobile apps). Tens of thousands of developers have developed hundreds of thousands of mobile apps that are available across multiple platforms. These apps are used by millions of people around the world every day. However, most software engineering research has been performed on large desktop or server applications.

We believe that research efforts must begin to examine mobile apps. Mobile apps are rapidly growing, yet they differ from traditionally-studied desktop/server applications.

In this thesis, we examine such apps by performing three quantitative studies. First, we study differences in the size of the code bases and development teams of desktop/server applications and mobile apps. We then study differences in the code, dependency and churn properties of mobile apps from two different mobile platforms. Finally, we study the impact of size, coupling, cohesion and code reuse on the quality of mobile apps.

Some of the most notable findings are that mobile apps are much smaller than traditionally-studied desktop/server applications and that most mobile apps tend to be developed by only one or two developers. Mobile app developers tend to rely heavily on functionality provided by the underlying mobile platform through platform-specific APIs. We find that Android app developers tend to rely on the Android platform more than BlackBerry app developers rely on the BlackBerry platform. We also find that defects in Android apps tend to be concentrated in a small number of files and that files that depend on the Android platform tend to have more defects.

Our results indicate that major differences exist between mobile apps and traditionally-studied desktop/server applications. However, the mobile apps of two different mobile platforms also differ. Further, our results suggest that mobile app developers should avoid excessive platform dependencies and focus their testing efforts on source code files that rely heavily on the underlying mobile platform. Given the widespread use of mobile apps and the lack of research surrounding these apps, we believe that our results will have significant impact on software engineering research.