How are framework code samples maintained and used by developers? The case of Android and Spring Boot

Modern software systems are commonly built on top of frameworks. To accelerate the learning process of features provided by frameworks, code samples are made available to assist developers. However, we know little about how code samples are developed and consumed. In this paper, we aim to fill this gap by assessing the characteristics of framework code samples. We provide insights into how code samples are maintained and used by developers. We analyze over 230 code samples provided by Android and Spring Boot, and assess aspects related to their code, evolution, popularity, and client usage. We find that most code samples are small and simple, provide a working environment for the clients, and rely on automated build tools. They frequently change, for example, to adapt to new framework versions. We also detect that clients commonly fork the code samples, however, they rarely modify them. To further understand the problems faced by developers, we analyze 614 Stack Overflow questions about the code samples and 269 issues from code sample repositories. We find that developers face problems when trying to modify the code samples and the most common issue is related to improvement. Finally, we propose implications to creators and clients of code samples to improve maintenance and usage activities.