Reasoning and Improving on Software Resilience against Unanticipated Exceptions

In software, there are the errors anticipated at specification and design time, those encountered at development and testing time, and those that happen in production mode yet never anticipated. In this paper, we aim at reasoning on the ability of software to correctly handle unanticipated exceptions. We propose an algorithm, called short-circuit testing, which injects exceptions during test suite execution so as to simulate unanticipated errors. This algorithm collects data that is used as input for verifying two formal exception contracts that capture two resilience properties. Our evaluation on 9 test suites, with 78% line coverage in average, analyzes 241 executed catch blocks, shows that 101 of them expose resilience properties and that 84 can be transformed to be more resilient

NPEFix: Automatic Runtime Repair of Null Pointer Exceptions in Java

Null pointer exceptions, also known as null dereferences are the number one exceptions in the field. In this paper, we propose 9 alternative execution semantics when a null pointer exception is about to happen. We implement those alternative execution strategies using code transformation in a tool called NPEfix. We evaluate our prototype implementation on 11 field null dereference bugs and 519 seeded failures and show that NPEfix is able to repair at runtime 10/11 and 318/519 failures

Software Engineering of Component-Based Systems-of-Systems: A Reference Framework

CORE A.International audienceSystems-of-Systems (SoS) are complex infrastructures, which are characterized by a wide diversity of technologies and requirements imposed by the domain(s) they target. In this context, the software engineering community has been focusing on assisting the developers by providing them domain-specific languages, component-based software engineering frameworks and tools to leverage on the design and the development of such systems. However, the adoption of such approaches often prevents developers from combining several domains, which is a strong requirement in the context of SoS. Furthermore, only little attention has been paid to the definition of a modular toolset and an extensible runtime infrastructure for deploying and executing SoS. In this paper, we therefore propose a reference framework to leverage on the software engineering of SoS. Our reference framework has been validated on the development of two platforms, namely Hulotte and FraSCAti, to demonstrate that the resulting complexity is isolated in the core toolset, while the development of domain-specific extensions is leveraged and simplified by clearly identified abstractions

Un ADL pour les Architectures Distribuées à Composants Hétérogènes

National audienceDans cet article, nous présentons un ADL pour les architectures à composants hétérogènes et distribuées, et son utilisation au moment du déploiement. Actuellement, il n'existe pas de solution générique pour déployer une architecture distribuée basée sur différents intergiciels. Pour répondre à cette problématique, nous proposons dans cet article une approche pour décrire une telle architecture et un support pour le déploiement. Notre solution s'appuie sur un langage de description d'architecture possédant des notions de dépendances verticales et horizontales. Un exemple simple est présenté pour illustrer notre langage et pour valider nos contributions

Informatique : Des logiciels mis au vert

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Dynamic Analysis can be Improved with Automatic Test Suite Refactoring

Context: Developers design test suites to automatically verify that software meets its expected behaviors. Many dynamic analysis techniques are performed on the exploitation of execution traces from test cases. However, in practice, there is only one trace that results from the execution of one manually-written test case. Objective: In this paper, we propose a new technique of test suite refactoring, called B-Refactoring. The idea behind B-Refactoring is to split a test case into small test fragments, which cover a simpler part of the control flow to provide better support for dynamic analysis. Method: For a given dynamic analysis technique, our test suite refactoring approach monitors the execution of test cases and identifies small test cases without loss of the test ability. We apply B-Refactoring to assist two existing analysis tasks: automatic repair of if-statements bugs and automatic analysis of exception contracts. Results: Experimental results show that test suite refactoring can effectively simplify the execution traces of the test suite. Three real-world bugs that could previously not be fixed with the original test suite are fixed after applying B-Refactoring; meanwhile, exception contracts are better verified via applying B-Refactoring to original test suites. Conclusions: We conclude that applying B-Refactoring can effectively improve the purity of test cases. Existing dynamic analysis tasks can be enhanced by test suite refactoring

Creating Context-Adaptive Business Processes

Acceptance rate : 15%, Rank (CORE) : AInternational audienceAs the dynamicity of today's business environments keeps increasing, there is a need to continuously adapt business processes in order to respond to the changes in those environments and keep a competitive level. By using complex event processing, we can discover information that is relevant to our organization, which is usually hidden among the data generated in the environment, and use it to adapt the processes accordingly in order to respond to the changing conditions in an optimal way. Unfortunately, the static nature of business process definitions makes it impossible to adapt them at runtime and the redeployment of a modified process is required. By using a component-based approach, we can transform the existing business processes into dynamically bound components, adding the flexibility needed to adapt the processes at runtime. In this paper we present CEVICHE, a framework that combines the strengths of complex event processing and dynamic business process adaptation, which allows to respond to the needs of the rapidly changing environment, and its adaptation language called SBPL, an extension to BPEL which adds flexibility to business processes

Managing Elasticity Across Multiple Cloud Providers

International audienceIn the context of cloud computing, elasticity is the capacity to scale computing resources up and down easily. Currently, most Platforms as a Service manage application elasticity within a single cloud provider. However, the not so infrequent issue of cloud outage has become a concern that hinders the usability of cloud-based applications. The most promising solutions to this issue are those based on the federation of multiple clouds. In this paper, we present a Multi-Cloud-PaaS architecture. We show how this architecture can be used for managing elasticity across multiple cloud providers