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Current practice in testing JavaScript web applications requires manual construction of test cases, which is difficult and tedious. We present a framework for feedback-directed automated test generation for JavaScript in which execution is monitored to collect information that directs the test generator towards inputs that yield increased coverage. We implemented several instantiations of the framework, corresponding to variations on feedback-directed random testing, in a tool called Artemis. Experiments on a suite of JavaScript applications demonstrate that a simple instantiation of the framework that uses event handler registrations as feedback information produces surprisingly good coverage if enough tests are generated. By also using coverage information and read-write sets as feedback information, a slightly better level of coverage can be achieved, and sometimes with many fewer tests. The generated tests can be used for detecting HTML validity problems and other programming errors.

Efficient storage and querying of RDF data is of increasing importance, due to the increased popularity and widespread acceptance of RDF on the web and in the enterprise. In this paper, we describe a novel storage and query mechanism for RDF which works on top of existing relational representations. Reliance on relational representations of RDF means that one can take advantage of 35+ years of research on efficient storage and querying, industrial-strength transaction support, locking, security, etc. However, there are significant challenges in storing RDF in relational, which include data sparsity and schema variability. We describe novel mechanisms to shred RDF into relational, and novel query translation techniques to maximize the advantages of this shredded representation. We show that these mechanisms result in consistently good performance across multiple RDF benchmarks, even when compared with current state-of-the-art stores. This work provides the basis for RDF support in DB2 v.10.1.

This paper describes the evolution of the Jikese Research Virtual Machine project from an IBM internal research project, called Jalapeñ o, into an open-source project. After summarizing the original goals of the project, we discuss the motivation for releasing it as an open-source project and the activities performed to ensure the success of the project. Throughout, we highlight the unique challenges of developing and maintaining an open-source project designed specifically to support a research community. On October 15, 2001, IBM Research launched the Jikes* RVM (Research Virtual Machine) open-source project.Jikes RVM provides a novel virtual-machine software infrastructure, suitable for research on modern programming language design and implementation techniques. Over the past three years, the project has grown and made a significant impact on the programming-language research community. This paper describes the evolution of Jikes RVM from an IBM internal research project, called Jalapeñ o, into a full-fledged open-source project. The story provides an instructive case study on how a small systems research project can grow into a shared project used by hundreds of researchers. The paper discusses a variety of challenges that arose in this process, including the technical enhancements and software-engineering practices needed to ensure the project's success; dealing with intellectual property, corporate process, and licensing issues;promoting the system in the research community; and developing a community to maintain and enhance the system in the future.The primary focus of the Jikes RVM project was the development of a software platform designed to be a research testbed for the prototyping of new technologies. In contrast, most open-source projects develop software products for use by the general public. We focus on the implications of this distinction throughout the paper.The remainder of this paper is as follows. The next section begins with a general discussion of issues Ó

Previously we presented atomic sets, memory locations that share some consistency property, and units of work, code fragments that preserve consistency of atomic sets on which they are declared. We also proposed atomic-set serializability as a correctness criterion for concurrent programs, stating that units of work must be serializable for each atomic set. We showed that a set of problematic data access patterns characterize executions that are not atomic-set serializable. Our criterion subsumes data races (single-location atomic sets) and serializability (all locations in one set).In this paper, we present a dynamic analysis for detecting violations of atomic-set serializability. The analysis can be implemented efficiently, and does not depend on any specific synchronization mechanism. We implemented the analysis and evaluated it on a suite of real programs and benchmarks. We found a number of known errors as well as several problems not previously reported.

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Abstract-Web script crashes and malformed dynamically generated webpages are common errors, and they seriously impact the usability of Web applications. Current tools for webpage validation cannot handle the dynamically generated pages that are ubiquitous on today's Internet. We present a dynamic test generation technique for the domain of dynamic Web applications. The technique utilizes both combined concrete and symbolic execution and explicit-state model checking. The technique generates tests automatically, runs the tests capturing logical constraints on inputs, and minimizes the conditions on the inputs to failing tests so that the resulting bug reports are small and useful in finding and fixing the underlying faults. Our tool Apollo implements the technique for the PHP programming language. Apollo generates test inputs for a Web application, monitors the application for crashes, and validates that the output conforms to the HTML specification. This paper presents Apollo's algorithms and implementation, and an experimental evaluation that revealed 673 faults in six PHP Web applications.