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Today's shared-memory parallel programming models are complex and error-prone.While many parallel programs are intended to be deterministic, unanticipated thread interleavings can lead to subtle bugs and nondeterministic semantics. In this paper, we demonstrate that a practical <i>type and effect system</i> can simplify parallel programming by(More)
One of the costs of reusing software components is migrating applications to use the new version of the components. Migrating an application can be error-prone, tedious, and disruptive of the development process. Our previous work shows that more than 80% of the disruptive changes in four different components were caused by refactorings. If the refactorings(More)
Refactorings are behavior-preserving program transformations that improve the design of a program. Refactoring engines are tools that automate the application of refactorings: first the user chooses a refactoring to apply, then the engine checks if the transformation is safe, and if so, transforms the program. Refactoring engines are a key component of(More)
SUMMARY Frameworks and libraries change their APIs. Migrating an application to the new API is tedious and disrupts the development process. Although some tools and ideas have been proposed to solve the evolution of APIs, most updates are done manually. To better understand the requirements for migration tools, we studied the API changes of four frameworks(More)
Identifying repetitive code changes benefits developers, tool builders, and researchers. Tool builders can automate the popular code changes, thus improving the productivity of developers. Researchers can better understand the practice of code evolution, advancing existing code assistance tools and benefiting developers even further. Unfortunately, existing(More)
Web script crashes and malformed dynamically-generated Web pages are common errors, and they seriously impact usability of Web applications. Current tools for Web-page validation cannot handle the dynamically-generated pages that are ubiquitous on today's Internet. In this work, we apply a dynamic test generation technique, based on combined concrete and(More)
Although in theory the APIs of software libraries and frameworks should be stable, they change in practice. This forces clients of the library API to change as well, making software maintenance expensive. Changing a client might not even be an option if its source code is missing or certain policies forbid its change. By giving a library both the old and(More)
Current text based Software Configuration Management (SCM) systems have trouble with refactorings. Refactorings result in global changes which lead to merge conflicts. A refactoring-aware SCM system reduces merge conflicts. This paper describes MolhadoRef, a refactoring-aware SCM system and the merge algorithm at its core. MolhadoRef records change(More)
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(More)
Despite the enormous success that manual and automated refactoring has enjoyed during the last decade, we know little about the practice of refactoring. Understanding the refactoring practice is important for developers, refactoring tool builders, and researchers. Many previous approaches to study refactorings are based on comparing code snapshots, which is(More)