On the Detection of Licenses Violations in the Android Ecosystem

Mobile applications (apps) developers often reuse code from existing libraries and frameworks in order to reduce development costs. However, these libraries and frameworks are governed by licenses to which developers must comply. A failure to comply with a license is likely to result in penalties and fines. In this paper, we analyse the licenses of 857 mobile apps from the F-droid market with the aim to understand the types of licenses that are mostly used by developers of open-source mobile apps and how these licenses evolve over time. We also investigate licenses violations and the evolution of these violations over time. Results show that developers of open-source mobile apps mostly use GPL and Apache licenses. We found licenses violations in 17 out of 857 apps, and 7 apps still had violations in their latest release at the time of this study. We also observed that many files are not licensed in their first release. Developers seem to have some difficulties understanding the legal constraints of licenses' terms.