Joint Proceedings of the Summer School on
Software Maintenance and Evolution

Editorial Board Members
Nyyti Saarimäki
Valentina Lenarduzzi
Davide Taibi


Preface
This volume contains the joint proceedings of two Inforte Summer Schools on software
maintenance and evolution arranged during the summer 2019: “​Software Quality and Bug
Prediction with Machine Learning​” organized on June 10-12 2019 and “​Summer School on
Software Evolution: From Monolithic to Cloud-Native​” organized on September 2-4 2019. ​Inforte
is a Finnish state wide programme for ICT professionals. It is designed to offer networking and
education events to PhD students and professionals working in Finnish companies, polytechnics and
public administration.


Program Committee
Fabio Palomba (University of Zurich)
Sebastiano Panichella (Zurich University of Applied Science)
Josef Spillner (Zurich University of Applied Science)
Valentina Lenarduzzi (Tampere University)
Davide Taibi (Tampere University)
Kari Systä (Tampere University)
Outi Sievi-Korte (Tampere University)
David Hästbacka (Tampere University)


Summer School on Software Quality and Bug Prediction with Machine Learning
June 10 –12, 2019, Tampere, Finland

The aim of the ​seminar was to familiarize the participants with different aspects of software quality
and different machine learning methods that can be used to predict it. The participants analyzed the
evolution and maintenance of software projects using machine learning and a given dataset. The
dataset provided the version history of technical debt issues for more than 30 open source software
projects at commit level, including information on commits, faults, technical issues and many more.
The analyses could be based on this dataset alone or expanded to also include data from other
resources such as GitHub. The overall goal was to study the evolution and maintenance of the
projects in the dataset.
At the end of the seminar, the participants were asked to finalize a paper on their project work. The
paper were peer-reviewed.
Invited Speaks
Software Design 101: Improving the Design of Existing Code, Tests, and Communities
Fabio Palomba, University of Zurich, Switzerland

In 1999, Martin Fowler introduced the concept of code smells, describing them as symptoms of
poor implementation choices that may possibly worsen source code design and induce software
faults. Besides keeping source code design under control, the continuous evolution of software
systems and the technologies associated with them - from Continuous Integration to DevOps - has
had the effect of putting in the spotlight tests and people, that are now more than ever required to
work in synergy with production code for the successful evolution of software systems. In this talk,
I will overview the state of the art with respect to empirical software engineering and mining
software repository methods that allow (i) the investigation and control of source code, test code,
and development community design and (ii) the analysis of the interactions among them.

Machine Learning Techniques for Bug Prediction
Valentina Lenarduzzi, Tampere University, Finland

Bug Prediction is one of software engineering’s holy grails, which concerns with the overall of
software successes. Predicting the software faults already from the earlier phase improves the
software quality, reliability, efficiency and reduces the maintenance cost. Developing robust bug
prediction model is a challenging task and many techniques have been proposed in the literature. In
this session, we will overview the state of the art of bug prediction model focusing on machine
learning techniques, looking at the selection, application and data management. In this session we
will provide a set of options to help students to select the most appropriate methods for their post
seminar challenge.


Summer School on Software Evolution: From Monolithic to Cloud-Native
September 2 –4, 2019, Tampere, Finland

Preface

The aim of the ​seminar was to familiarize the participants with software evolution in the cloud.
Participants were invited to submit papers on cloud-native system, software evolution in the cloud,
microservices and serverless. Papers were peer-reviewed by the program committee
Invited speaks
Cloud Native Migration Patterns
Davide Taibi

Cloud-Native technologies, and especially microservices are enjoying increasing popularity and
diffusion in industrial environments, being adopted by several big players such as Amazon,
LinkedIn, Netflix, and SoundCloud. Several patterns and platforms such as nginx (​www.nginx.org​)
and Kubernetes (kubernetes.io) exist on the market. During the migration process, practitioners
often face common problems, which are mainly due to their lack of knowledge regarding bad
practices and patterns. In this session, we provide an introduction of the cloud-native patterns,
reporting their issues and motivations, and describing the most common patterns and anti-patterns.


Cloud-based Testing
Sebastiano Panichella, University of Zurich, Switzerland

To promote and sustain the future of our society, the most critical challenge of contemporary
software engineering and cloud computing experts are related to the efficient integration of
emerging cloudification and DevOps practices in the development and testing processes of modern
systems.
In this context, we argue that Search-based Software testing (SBST) can play a critical role in
improving testing practices and automating the verification and validation (V&V) of cloudification
properties of Cloud Native Applications (CNA). We, we focus on the untouched side of SBST in
the cloud field, by discussing (1) the testing challenges in the cloud research field and (2)
summarizing the recent contributions of SBST in supporting development practices of CNA. Then,
we discuss the emerging research topics characterizing the cloudification perspectives of SBST in
the cloud field. Finally, we provide evidence on how
SBST can used to improve testing practices in the context of cloud-native applications.


Software evolution in microservice artefacts
Josef Spillner, Zurich University of Applied Sciences, Switzerland

Modern cloud software applications are characterised by mixed-technology compositions of
stateless and stateful artefacts, many of them representing microservices. Through open
marketplaces, both generic and artefact type-specific ones, it is possible to learn about the evolution
of artefacts and microservices over time. Specifically, metrics related to the supply and demand side
- published and downloaded or deployed artefacts - and technical metrics related to code and
configuration are already measured in long-term experiments by researchers. This talk outlines
current artefact observations, identifies common trends and diverging metrics, and explains how
researchers can exploit the information gained from the evolution to help developers build better
cloud software.
Kubernetes, Operators SDK, and Prometheus
Sebastiano Panichella, University of Zurich, Switzerland

Emerging technologies are used to perform the verification and validation (V&V) of cloudification
properties of Cloud Native Applications (CNA) as well as to enable a better observability,
monitoring, and management of these applications. In this talk we provide some hands-on and
practical insights on the most emerging technologies characterizing the emerging cloud computing
and software engineering research: Kubernetes, Operators SDK, and Prometheus. Then, we discuss
the emerging research topics characterizing the usage of such tools the context of cloud-native
applications.


Cloud service dependencies in practice
Josef Spillner, Zurich University of Applied Sciences, Switzerland

In theory, software and service dependencies are simple. They are simple to define through
declarative files, simple to resolve by package managers and service brokers, and simple to
understand. In practice, they are hard. Dependencies are often implicit, nested or transitive,
conflicting, and moving targets. This talk first conveys general knowledge about dependencies,
presents algorithms for deterministic and heuristic dependency detection, and then explores them in
popular composite (orchestrated) application formats. The talk also touches on the related topic of
software application portability. 11:30 - 12:30 “Students presentation” students will make a short
presentation (10 min per student) where they will present 1) their Ph.D. topics, 2) the research
questions they are planning to investigate 3) the research techniques they are planning to apply