Despite over 3.5 million Android apps and 200+ million Android Auto-compatible vehicles, only a few hundred apps support Android Auto due to platform-specific compliance requirements. Android Auto mandates service-based architectures in which the vehicle system invokes app callbacks to render the UI and handle interactions, which is fundamentally different from standard Activity-based Android development. Through an empirical study analysis of 98 issues across 14 Android Auto app repositories, we identified three major compliance failure categories: media playback errors, UI rendering issues, and voice command integration failures in line with mandatory requirements for integrating Android Auto support. We introduce AutoComply, a static analysis framework capable of detecting these compliance violations through the specialized analysis of platform-specific requirements. AutoComply constructs a Car-Control Flow Graph (CCFG) extending traditional control flow analysis to model the service-based architecture of Android Auto apps. Evaluating AutoComply on 31 large-scale open-source apps, it detected 27 violations (13 × more than Android Lint), while no false positives were observed, achieving 2 × faster analysis. Developers have acknowledged 14 of these violations with 8 fixes already implemented, validating AutoComply’s practical effectiveness.

Many program analyses can be formulated as context-free language (CFL) reachability problems on an edge-labeled graph.While graph systems have been proposed recently for large-scale CFL reachability analysis of system software, the design space has not yet been systematically explored, leading to sub-optimal performance.This work presents GraCFL 1 , a holistically designed graph system for CFL reachability.Inspired by the vertex-centric processing paradigm, we formalize CFL reachability using a multi-directional vertex-centric model.We then analyze this model in terms of computation redundancy, strategies for deriving new reachability, data locality, and parallelism.The analysis reveals a set of insights that guide the design of new techniques and optimizations to improve system performance.As a result of the systematic design, GraCFL demonstrates superior performance compared to state-ofthe-art graph systems, with an average 14.14× speedup over Graspan and 8.33× speedup over POCR.Its source code is available at https://github.com/AutomataLab/GraCFL.

Userland memory forensics has become a critical component of smartphone investigations and incident response, enabling the recovery of volatile evidence such as deleted messages from end-to-end encrypted apps and cryptocurrency transactions. However, these forensics tools, particularly on Android, face significant challenges in adapting to different versions and maintaining reliability over time due to the constant evolution of low-level structures critical for evidence recovery and reconstruction. Structural changes, ranging from simple offset modifications to complete architectural redesigns, pose substantial maintenance and adaptability issues for forensic tools that rely on precise structure interpretation. Thus, this paper presents the first systematic study of Android Runtime (ART) structural evolution and its implications for memory forensics. We conduct an empirical analysis of critical Android runtime structures, examining their evolution across six versions for four different architectures. Our findings reveal that over $73.2 \%$ of structure members underwent positional changes, significantly affecting the adaptability and reliability of memory forensic tools. Further analysis of core components such as Runtime, Thread, and Heap structures highlights distinct evolution patterns and their impact on critical forensic operations, including thread state enumeration, memory mapping, and object reconstruction. These results demonstrate that traditional approaches relying on static structure definitions and symbol-based methods, while historically reliable, are increasingly unsustainable on their own. We recommend that memory forensic tools in general and Android in particular evolve toward hybrid approaches that retain the validation strength of symbolic methods while integrating automated structure inference, version-aware parsing, and redundant analysis strategies. These adaptations are essential for sustaining effective and trustworthy forensic capabilities amidst rapidly evolving runtime environments.

A common feature in Android apps is saving, or exporting, user’s work (e.g., a drawing) as well as data (e.g., a spreadsheet) onto local storage, as a file. Due to the volatile nature of the OS and the mobile environment in general, the system can terminate apps without notice, which prevents the execution of file write operations; consequently, user data that was supposed to be saved/exported is instead lost. Testing apps for such potential losses raises several challenges: how to identify data originating from user input or resulting from user action (then check whether it is saved), and how to reproduce a potential error by terminating the app at the exact moment when unsaved changes are pending. We address these challenges via an approach that finds potential “lost writes”, i.e., user data supposed to be written to a file, but the file write does not take place due to system-initiated termination. Our approach consists of two phases: a static analysis that finds potential losses and a dynamic loss verification phase where we compare lossy and lossless system-level file write traces to confirm errors. We ran our analysis on 2,182 apps from Google Play and 38 apps from F-Droid. Our approach found 163 apps where termination caused losses, including losing user’s app-specific data, notes, photos, user’s work and settings. In contrast, two state-of-the-art tools aimed at finding volatility errors in Android apps failed to discover the issues we found.

Modern mobile applications have grown rapidly in binary size, which restricts user growth and hinders updates for existing users. Thus, reducing the binary size is important for application developers. Recent studies have shown the possibility of using link-time code size optimizations by re-invoking certain compiler optimizations on the linked intermediate representation of the program. However, such methods often incur significant build time overhead and require intrusive changes to the existing build pipeline.

Recommender systems have become ubiquitous in our digital lives, from recommending products on e-commerce websites to suggesting movies and music on streaming platforms. Existing recommendation datasets, such as Amazon Product Reviews and MovieLens, greatly facilitated the research and development of recommender systems in their respective domains. While the number of mobile users and applications (aka apps) has increased exponentially over the past decade, research in mobile app recommender systems has been significantly constrained, primarily due to the lack of high-quality benchmark datasets, as opposed to recommendations for products, movies, and news. To facilitate research for app recommendation systems, we introduce a large-scale dataset, called MobileRec. We constructed MobileRec from users' activity on the Google play store. MobileRec contains 19.3 million user interactions (i.e., user reviews on apps) with over 10K unique apps across 48 categories. MobileRec records the sequential activity of a total of 0.7 million distinct users. Each of these users has interacted with no fewer than five distinct apps, which stands in contrast to previous datasets on mobile apps that recorded only a single interaction per user. Furthermore, MobileRec presents users' ratings as well as sentiments on installed apps, and each app contains rich metadata such as app name, category, description, and overall rating, among others. We demonstrate that MobileRec can serve as an excellent testbed for app recommendation through a comparative study of several state-of-the-art recommendation approaches. The MobileRec dataset is available at https://huggingface.co/datasets/recmeapp/mobilerec.

Mobile app stores produce a tremendous amount of data in the form of user reviews, which is a huge source of user requirements and sentiments; such reviews allow app developers to proactively address issues in their apps. However, only a small number of reviews capture common issues and sentiments which creates a need for automatically identifying prominent reviews. Unfortunately, most existing work in text ranking and popularity prediction focuses on social contexts where other signals are available, which renders such works ineffective in the context of app reviews. In this work, we propose a new framework, PPrior, that enables proactive prioritization of app issues through identifying prominent reviews (ones predicted to receive a large number of votes in a given time window). Predicting highly-voted reviews is challenging given that, unlike social posts, social network features of users are not available. Moreover, there is an issue of class imbalance, since a large number of user reviews receive little to no votes. PPrior employs a pre-trained T5 model and works in three phases. Phase one adapts the pre-trained T5 model to the user reviews data in a self-supervised fashion. In phase two, we leverage contrastive training to learn a generic and task-independent representation of user reviews. Phase three uses radius neighbors classifier t o m ake t he final predictions. This phase also uses FAISS index for scalability and efficient search. To conduct extensive experiments, we acquired a large dataset of over 2.1 million user reviews from Google Play. Our experimental results demonstrate the effectiveness of the proposed framework when compared against several state-of-the-art approaches. Moreover, the accuracy of PPrior in predicting prominent reviews is comparable to that of experienced app developers.

Hundreds of thousands of mobile app users post their reviews online. Responding to user reviews promptly and satisfactorily improves application ratings, which is key to application popularity and success. The proliferation of such reviews makes it virtually impossible for developers to keep up with responding manually. To address this challenge, recent work has shown the possibility of automatic response generation by training a seq2seq model with a large collection of review-response pairs. However, because the training review-response pairs are aggregated from many different apps, it remains challenging for such models to generate app-specific responses, which, on the other hand, are often desirable as appwes have different features and concerns. Solving the challenge by simply building an app-specific generative model per app (i.e., training the model with review-response pairs of a single app) may be insufficient because individual apps have limited review-response pairs, and such pairs typically lack the relevant information needed to respond to a new review.To enable app-specific response generation, this work proposes AARSYNTH: an app-aware response synthesis system. The key idea behind AARSYNTH is to augment the seq2seq model with information specific to a given app. Given a new user review, AARSYNTH first retrieves the top-K most relevant app reviews and the most relevant snippet from the app description. The retrieved information and the new user review are then fed into a fused machine learning model that integrates the seq2seq model with a machine reading comprehension model. The latter helps digest the retrieved reviews and app description. Finally, the fused model generates a response that is customized to the given app. We evaluated AARSYNTH using a large corpus of reviews and responses from Google Play. The results show that AARSYNTH outperforms the state-of-the-art system by 22.2% on BLEU-4 score. Furthermore, our human study shows that AARSYNTH produces a statistically significant improvement in response quality compared to the state-of-the-art system.

Mobile operating systems, especially Android, expose apps to a volatile runtime environment. The app state that reflects past user interaction and system environment updates (e.g., battery status changes) can be destroyed implicitly, in response to runtime configuration changes (e.g., screen rotations) or memory pressure. Developers are therefore responsible for identifying app state affected by volatility and preserving it across app lifecycles. When handled inappropriately, the app may lose state or end up in an inconsistent state after a runtime configuration change or when users return to the app. To free developers from this tedious and error-prone task, we propose a systematic solution, LiveDroid, which precisely identifies the necessary part of the app state that needs to be preserved across app lifecycles, and automatically saves and restores it. LiveDroid consists of: (i) a static analyzer that reasons about app source code and resource files to pinpoint the program variables and GUI properties that represent the necessary app state, and (ii) a runtime system that manages the state saving and recovering. We implemented LiveDroid as a plugin in Android Studio and a patching tool for APKs. Our evaluation shows that LiveDroid can be successfully applied to 966 Android apps. A focused study with 36 Android apps shows that LiveDroid identifies app state much more precisely than an existing solution that includes all mutable program variables but ignores GUI properties. As a result, on average, LiveDroid is able to reduce the costs of state saving and restoring by 16.6X (1.7X - 141.1X) and 9.5X (1.1X - 43.8X), respectively. Furthermore, compared with the manual state handling performed by developers, our analysis reveals a set of 46 issues due to incomplete state saving/restoring, all of which can be successfully eliminated by LiveDroid.

JSON (JavaScript Object Notation) and its derivatives are essential in the modern computing infrastructure. However, existing software often fails to process such types of data in a scalable way, mainly for two reasons: (i) the processing often requires to build a memory-consuming parse tree; (ii) there exist inherent dependences in processing the data stream, preventing any data-level parallelization. Facing the challenges, developers often have to construct ad-hoc pre-parsers to split the data stream in order to reduce the memory consumption and increase the data parallelism. However, this strategy requires more programming efforts. Moreover, the pre-parsing itself is non-trivial to parallelize, thus introducing a new serial bottleneck. To solve the dilemma, this work introduces a scalable yet fully automatic solution - a compilation system, namely JPStream, that compiles standard JSONPath queries into parallel executables with bounded memory footprints. First, JPStream adopts a stream processing design that combines the querying and parsing into one pass, without generating any in-memory parse tree. To achieve this, JPStream uses a novel joint compilation technique that compiles the queries and the JSON syntax together into a single automaton. Furthermore, JPStream leverages the "enumerability'' of automaton to break the dependences and reason about the transition rules to prune infeasible states. It also features a runtime that learns structural constraints from the input to enhance the pruning. Evaluation on real-world JSON datasets with standard JSONPath queries shows that JPStream can reduce the memory consumption significantly, by up to 95%, meanwhile achieving near-linear speedup on multicore and manycore processors.

Portable devices, like smartphones and tablets, are often subject to runtime configuration changes, such as screen orientation changes, screen resizing, keyboard attachments, and language switching. When handled improperly, such simple changes can cause serious runtime issues, from data loss to app crashes.