Retrofitting concurrency for Android applications through refactoring

Abstract

Running compute-intensive or blocking I/O operations in the UI event thread of smartphone apps can severely degrade responsiveness. Despite the fact that Android supports writing concurrent code via AsyncTask, we know little about how developers use AsyncTask to improve responsiveness. To understand how AsyncTask is used/underused/misused in practice, we first conduct a formative study using a corpus of 104 open-source Android apps comprising 1.34M SLOC. Our study shows that even though half of the apps use AsyncTask, there are hundreds of places where they missed opportunities to encapsulate long-running operations in AsyncTask. Second, 46% of the usages are manually refactored. However, the refactored code contains concurrency bugs (such as data races) and performance bugs (concurrent code still executes sequentially).Inspired by these findings, we designed, developed, and evaluated Asynchronizer, an automated refactoring tool that enables developers to extract long-running operations into AsyncTask. Asynchronizer uses a points-to static analysis to determine the safety of the transformation. Our empirical evaluation shows that Asynchronizer is (i) highly applicable, (ii) accurate, (iii) safer than manual refactoring (iv) it saves development effort, (v) its results have been accepted by the open-source developers. This shows that Asynchronizer is useful.

Improving responsiveness in mobile apps via refactoring for asynchrony (invited talk)

“…Asynchronizer uses a points-to static analysis to determine the safety of the transformation. The empirical evaluation presented in our paper [11] shows that Asynchronizer is useful.…”

“…In our formative studies [11,13], we found that half of all asynchrony usages in real-world programs have not been introduced from scratch, but have been converted from previously existing synchronous code. This step is a source-to-source transformation that needs to preserve the current functionality of the application (albeit improve some non-functional property such as responsiveness), thus it is a refactoring [6].…”

Static detection of energy defect patterns in Android applications

“…Other static analyses also model the sequences of callbacks in Android, for the purposes of race detection �e.g., [24]), leak analysis �e.g., [18]), and static checking �e.g., [37,50]); all these approaches employ ad hoc control-flow modeling that lacks generality.…”

A large-scale study on the usage of Java’s concurrent programming constructs

“…However, due to the cost of the analysis that was performed, it examines a small number of systems. Lin et al (2014) had analyzed 104 open-source Android applications in order to understand how AsyncTask (a high-level concurrent construct) is used by programmers, if it is misused and underused. Marinescu (2014) also analyzed SourceForge, but she focuses on MPI (Message Passing Interface), a concurrent programming construct used in the C programming language.…”