Detailed Overview of Software Smells

This document provides an overview of literature concerning software smells covering various dimensions of smells along with their corresponding references

Detection of microservice smells through static analysis

A arquitetura de microsserviços é um modelo arquitetural promissor na área de software, atraindo desenvolvedores e empresas para os seus princípios convincentes. As suas vantagens residem no potencial para melhorar a escalabilidade, a flexibilidade e a agilidade, alinhando se com as exigências em constante evolução da era digital. No entanto, navegar entre as complexidades dos microsserviços pode ser uma tarefa desafiante, especialmente à medida que este campo continua a evoluir. Um dos principais desafios advém da complexidade inerente aos microsserviços, em que o seu grande número e interdependências podem introduzir novas camadas de complexidade. Além disso, a rápida expansão dos microsserviços, juntamente com a necessidade de aproveitar as suas vantagens de forma eficaz, exige uma compreensão mais profunda das potenciais ameaças e problemas que podem surgir. Para tirar verdadeiramente partido das vantagens dos microsserviços, é essencial enfrentar estes desafios e garantir que o desenvolvimento e a adoção de microsserviços sejam bem-sucedidos. O presente documento pretende explorar a área dos smells da arquitetura de microsserviços que desempenham um papel tão importante na dívida técnica dirigida à área dos microsserviços. Embarca numa exploração de investigação abrangente, explorando o domínio dos smells de microsserviços. Esta investigação serve como base para melhorar um catálogo de smells de microsserviços. Esta investigação abrangente obtém dados de duas fontes primárias: systematic mapping study e um questionário a profissionais da área. Este último envolveu 31 profissionais experientes com uma experiência substancial no domínio dos microsserviços. Além disso, são descritos o desenvolvimento e o aperfeiçoamento de uma ferramenta especificamente concebida para identificar e resolver problemas relacionados com os microsserviços. Esta ferramenta destina-se a melhorar o desempenho dos programadores durante o desenvolvimento e a implementação da arquitetura de microsserviços. Por último, o documento inclui uma avaliação do desempenho da ferramenta. Trata-se de uma análise comparativa efetuada antes e depois das melhorias introduzidas na ferramenta. A eficácia da ferramenta será avaliada utilizando o mesmo benchmarking de microsserviços utilizado anteriormente, para além de outro benchmarking para garantir uma avaliação abrangente.The microservices architecture stands as a beacon of promise in the software landscape, drawing developers and companies towards its compelling principles. Its appeal lies in the potential for improved scalability, flexibility, and agility, aligning with the ever-evolving demands of the digital age. However, navigating the intricacies of microservices can be a challenging task, especially as this field continues to evolve. A key challenge arises from the inherent complexity of microservices, where their sheer number and interdependencies can introduce new layers of intricacy. Furthermore, the rapid expansion of microservices, coupled with the need to harness their advantages effectively, demands a deeper understanding of the potential pitfalls and issues that may emerge. To truly unlock the benefits of microservices, it is essential to address these challenges head-on and ensure a successful journey in the world of microservices development and adoption. The present document intends to explore the area of microservice architecture smells that play such an important role in the technical debt directed to the area of microservices. It embarks on a comprehensive research exploration, delving into the realm of microservice smells. This research serves as the cornerstone for enhancing a microservice smell catalogue. This comprehensive research draws data from two primary sources: a systematic mapping research and an industry survey. The latter involves 31 seasoned professionals with substantial experience in the field of microservices. Moreover, the development and enhancement of a tool specifically designed to identify and address issues related to microservices is described. This tool is aimed at improving developers' performance throughout the development and implementation of microservices architecture. Finally, the document includes an evaluation of the tool's performance. This involves a comparative analysis conducted before and after the tool's enhancements. The tool's effectiveness will be assessed using the same microservice benchmarking as previously employed, in addition to another benchmark to ensure a comprehensive evaluation

COBOL systems migration to SOA: Assessing antipatterns and complexity

SOA and Web Services allow users to easily expose business functions to build larger distributed systems. However, legacy systems - mostly in COBOL - are left aside unless applying a migration approach. The main approaches are direct and indirect migration. The former implies wrapping COBOL programs with a thin layer of a Web Service oriented language/platform. The latter needs reengineering COBOL functions to a modern language/ platform. In our previous work, we presented an intermediate approach based on direct migration where developed Web Services are later refactored to improve the quality of their interfaces. Refactorings mainly capture good practices inherent to indirect migration. For this, antipatterns for WSDL documents (common bad practices) are detected to prevent issues related to WSDLs understanding and discoverability. In this paper, we assess antipatterns of Web Services’ WSDL documents generated upon the three migration approaches. In addition, generated Web Services’ interfaces are measured in complexity to attend both comprehension and interoperability. We apply a metric suite (by Baski & Misra) to measure complexity on services interfaces - i.e., WSDL documents. Migrations of two real COBOL systems upon the three approaches were assessed on antipatterns evidences and the complexity level of the generated SOA frontiers - a total of 431 WSDL documents.Fil: Mateos Diaz, Cristian Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Instituto Superior de Ingeniería del Software. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto Superior de Ingeniería del Software; ArgentinaFil: Zunino Suarez, Alejandro Octavio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Instituto Superior de Ingeniería del Software. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto Superior de Ingeniería del Software; ArgentinaFil: Flores, Andrés Pablo. Universidad Nacional del Comahue. Facultad de Informática. Departamento Ingeniería de Sistemas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Misra, Sanjay. Atilim University; Turquía. Covenant University; Nigeri

A Survey of Performance Optimization for Mobile Applications

Nowadays there is a mobile application for almost everything a user may think of, ranging from paying bills and gathering information to playing games and watching movies. In order to ensure user satisfaction and success of applications, it is important to provide high performant applications. This is particularly important for resource constraint systems such as mobile devices. Thereby, non-functional performance characteristics, such as energy and memory consumption, play an important role for user satisfaction. This paper provides a comprehensive survey of non-functional performance optimization for Android applications. We collected 155 unique publications, published between 2008 and 2020, that focus on the optimization of non-functional performance of mobile applications. We target our search at four performance characteristics, in particular: responsiveness, launch time, memory and energy consumption. For each performance characteristic, we categorize optimization approaches based on the method used in the corresponding publications. Furthermore, we identify research gaps in the literature for future work

Analysis of Microservice Coupling Measures

Microservices architectures are composed of a collection of modular, fault-tolerant services. In recent years, the software engineering community has published research on viable, recurring, and effective architectural patterns in microservices-based architectures, as they are critical to the maintenance and scaling of microservice-based systems. As well as, ensuring low coupling and strong cohesion among the microservices that comprise the cloud-native application is a crucial property.Services that are loosely connected and highly coherent allow development teams to work in parallel, eliminating communication overhead between teams. In the first section of this thesis, we attempted to generate a dataset by starting with a selected list of microservice-based projects. The collection is made up of 20 open-source applications that all use certain microservice architecture patterns. Furthermore, the dataset includes information about the aforementioned projects’ interservice calls and dependencies. In the second section, we suggested methods for computing and visualizing the coupling be- tween microservices by expanding and adapting the notions underlying standard of structural coupling calculation. We validate these measures using a case study of 17 projects selected from the aforementioned dataset, and we propose an automated method for measuring them. The findings of this study emphasize how these metrics give practitioners with quantitative and visual views of service architecture, that can be used to design advanced measures to monitor the development of services

Explainable, Security-Aware and Dependency-Aware Framework for Intelligent Software Refactoring

As software systems continue to grow in size and complexity, their maintenance continues to become more challenging and costly. Even for the most technologically sophisticated and competent organizations, building and maintaining high-performing software applications with high-quality-code is an extremely challenging and expensive endeavor. Software Refactoring is widely recognized as the key component for maintaining high-quality software by restructuring existing code and reducing technical debt. However, refactoring is difficult to achieve and often neglected due to several limitations in the existing refactoring techniques that reduce their effectiveness. These limitation include, but not limited to, detecting refactoring opportunities, recommending specific refactoring activities, and explaining the recommended changes. Existing techniques are mainly focused on the use of quality metrics such as coupling, cohesion, and the Quality Metrics for Object Oriented Design (QMOOD). However, there are many other factors identified in this work to assist and facilitate different maintenance activities for developers: 1. To structure the refactoring field and existing research results, this dissertation provides the most scalable and comprehensive systematic literature review analyzing the results of 3183 research papers on refactoring covering the last three decades. Based on this survey, we created a taxonomy to classify the existing research, identified research trends and highlighted gaps in the literature for further research. 2. To draw attention to what should be the current refactoring research focus from the developers’ perspective, we carried out the first large scale refactoring study on the most popular online Q&A forum for developers, Stack Overflow. We collected and analyzed posts to identify what developers ask about refactoring, the challenges that practitioners face when refactoring software systems, and what should be the current refactoring research focus from the developers’ perspective. 3. To improve the detection of refactoring opportunities in terms of quality and security in the context of mobile apps, we designed a framework that recommends the files to be refactored based on user reviews. We also considered the detection of refactoring opportunities in the context of web services. We proposed a machine learning-based approach that helps service providers and subscribers predict the quality of service with the least costs. Furthermore, to help developers make an accurate assessment of the quality of their software systems and decide if the code should be refactored, we propose a clustering-based approach to automatically identify the preferred benchmark to use for the quality assessment of a project. 4. Regarding the refactoring generation process, we proposed different techniques to enhance the change operators and seeding mechanism by using the history of applied refactorings and incorporating refactoring dependencies in order to improve the quality of the refactoring solutions. We also introduced the security aspect when generating refactoring recommendations, by investigating the possible impact of improving different quality attributes on a set of security metrics and finding the best trade-off between them. In another approach, we recommend refactorings to prioritize fixing quality issues in security-critical files, improve quality attributes and remove code smells. All the above contributions were validated at the large scale on thousands of open source and industry projects in collaboration with industry partners and the open source community. The contributions of this dissertation are integrated in a cloud-based refactoring framework which is currently used by practitioners.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/171082/1/Chaima Abid Final Dissertation.pdfDescription of Chaima Abid Final Dissertation.pdf : Dissertatio

An Approach for Guiding Developers to Performance and Scalability Solutions

This thesis proposes an approach that enables developers who are novices in software performance engineering to solve software performance and scalability problems without the assistance of a software performance expert. The contribution of this thesis is the explicit consideration of the implementation level to recommend solutions for software performance and scalability problems. This includes a set of description languages for data representation and human computer interaction and a workflow

Exploring and categorizing maintainability assurance research for service and microservice-based systems

Im Laufe des Softwarelebenszyklus eines Programms innerhalb einer sich ständig wechselnden Softwareumgebung ist es wahrscheinlich, dass dieses Programm regelmäßig gewartet werden muss. Wartungen kosten Geld und somit ist es wichtig, dass ebensolche Wartungen effizient und effektiv durchgeführt werden können. Im Laufe der Geschichte der Softwareentwicklung traten unter anderem zwei Architekturmuster hervor: Serviceorientierte Architektur und Microservices. Da diese Architekturmuster ein hohes Maß an Wartbarkeit versprechen, wurden viele Altsysteme hin zu diesen modernen Architekturen migriert. Es kann fatale Folgen für Unternehmen haben, wenn Änderungen an einem System nicht schnell, risikofrei und fehlerfrei umgesetzt werden können. Es wurden bereits viele Forschungsarbeiten bezogen auf die Wartbarkeit von serviceorientierter Architektur publiziert. Systeme basierend auf Microservices fanden jedoch, bezogen auf Wartbarkeitssicherung, nicht viel Beachtung. Sämtliche Forschungsarbeiten befinden sich verteilt auf viele Literaturdatenbanken, wodurch ein umfassender Überblick erschwert wird. Um einen solchen Überblick bereitzustellen, führten wir im Rahmen dieser Bachelorarbeit eine systematische Literaturstudie durch, die sich mit der Wartbarkeitssicherung von serviceorienter Architektur und Systemen basierend auf Microservices beschäftigt. Zur Durchführung dieser systematischen Literaturstudie entwickelten wir eine Reihe von relevanten Forschungsfragen sowie ein striktes Forschungsprotokoll. Aufbauend auf diesem Protokoll sammelten wir insgesamt 223 Forschungsarbeiten von verschiedenen Herausgebern. Diese Arbeiten wurden bezüglich ihres Inhalts zuerst in drei Gruppen von Kategorien unterteilt (architektonisch, thematisch und methodisch). Danach wurden die jeweils relevantesten Forschungsrichtungen aus jeder thematischen Kategorie herausgearbeitet und vorgestellt. Zum Abschluss wurden deutliche Unterschiede der in den Forschungsarbeiten präsentierten Inhalte in Bezug auf serviceorientierte Architektur und Microservice-basierte Systeme herausgearbeitet und dargestellt. Unsere Ergebnisse zeigten eine deutliche Unterrepräsentation von Forschungsarbeiten zur Wartbarkeitssicherung für Microservice-basierte Systeme. Während der Untersuchung der Kategorien konnten wir diverse Forschungsrichtungen innerhalb dieser feststellen. Ein Beispiel hierfür ist die Forschungsrichtung "change impact in business processes" in der Kategorie "Change Impact and Scenarios". Abschließend konnten wir einige Unterschiede bezogen auf die gesammelten Forschungsarbeiten zwischen Systemen basierend auf einer serviceorientierten Architektur und Systemen basierend auf Microservices feststellen. Ein solcher Unterschied kann zum Beispiel in der Kategorie "Antipatterns and Bad Smells" gefunden werden. Im Vergleich zu Forschungsarbeiten, welche sich auf serviceorientierte Architektur beziehen, beinhalten Forschungsarbeiten im Zusammenhang mit Systemen auf Basis von Microservices nur grundlegende Informationen zu Antipatterns, jedoch keine Herangehensweisen, um diese zu erkennen. Aufgrund unserer Ergebnisse schlagen wir einen stärkeren Fokus auf Forschung zur Wartbarkeitssicherung in Microservice-basierten Systemen vor. Mögliche zukünftige Forschungsarbeiten könnten überprüfen, ob Herangehensweisen zur Wartbarkeitssicherung von serviceorientierter Architektur auch bei Microservices anwendbar sind. Darüber hinaus schlagen wir die Durchführung von systematischen Literaturstudien vor, welche Themen wie "runtime adaptation", "testing" und "legacy migration" untersuchen, da diese Themen in unserer Literaturstudie ausgeschlossen wurden.It is very likely that software running in an everchanging environment needs to evolve at multiple points during its lifecycle. Because maintenance costs money, it is important for such tasks to be as effective and efficient as possible. During the history of software development service- and microservice-based architectures have emerged among other architectures. Since these architectures promise to provide a high maintainability, many legacy systems are or were migrated towards a service- or microservice-based architecture. In order to keep such systems running, maintenance is inevitable. While a lot of research has been published regarding maintainability assurance for service-based systems, microservice-based systems have not gotten a lot of attention. All published research is spread across several scientific databases which makes it difficult to get an extensive overview of existing work. In order to provide such overview of maintainability assurance regarding service- and microservice-based systems, we conducted a systematic literature review. To support our literature review, we developed a set of meaningful research questions and a rigid research protocol. Based on our protocol we collected a set of 223 different papers. These papers were first categorized into a threefold set of categories (architectural, thematical and methodical). After that, the most relevant research directions from each thematical category were extracted and presented. Lastly, we extracted and presented notable differences between approaches relating to service-oriented architecture or microservice-based systems. Our findings show a clear underrepresentation of maintainability assurance approaches suitable for microservice-based systems. We further discovered that regarding our formed categories, we could find several research directions such as change impact in business processes in "Change Impact and Scenarios". In the end, we could identify some differences between service- and microservice-based systems concerning approaches we retrieved in this thesis. A difference, for example was that in comparison with papers related to service-oriented architecture in "Antipatterns and Bad Smells", microservices related papers only contained basic information on antipatterns, but no approaches to detect them. Due to our findings we suggest a higher participation in research regarding maintainability assurance for microservice-based systems. Possible future work in this area could include further research on the applicability of service-oriented maintainability assurance approaches or techniques in microservice-based systems. Furthermore, future researchers could conduct follow-up literature reviews and investigate topics such as runtime adaptation, testing and legacy migration, since we excluded such topics from this thesis