This Festschrift, dedicated to Reiner Hahnle on the occasion of his 60th birthday, contains papers written by many of his closest collaborators.After positions at Karlsruhe Institute of Technology and Chalmers University of Technology, since 2011 Reiner has been the chaired professor of Software Engineering at Technische Universitat Darmstadt, where his team focuses on the formal verification of object-oriented software, the formal modeling and specification of highly adaptive software systems, and formal modeling and analysis in domains such as biological systems and railroad operations. His work is characterized by achievements in theory and in practical implementations, significant collaborations include the KeY project and the development of the ABS language. He has served as chair and editor of important related academic conferences, and coauthored almost 200 academic publications. The contributions in this volume reflect Reiner's main research focus: formal methods, in particular applied to software verification.

This book presents reflections on the occasion of 20 years on the KeY project that focuses on deductive software verification.Since the inception of the KeY project two decades ago, the area of deductive verification has evolved considerably. Support for real world programming languages by deductive program verification tools has become prevalent. This required to overcome significant theoretical and technical challenges to support advanced software engineering and programming concepts. The community became more interconnected with a competitive, but friendly and supportive environment. We took the 20-year anniversary of KeY as an opportunity to invite researchers, inside and outside of the project, to contribute to a book capturing some state-of-the-art developments in the field. We received thirteen contributions from recognized experts of the field addressing the latest challenges. The topics of the contributions range from tool development, effciency and usability considerations to novel specification and verification methods. This book should offer the reader an up-to-date impression of the current state of art in deductive verification, and we hope, inspire her to contribute to the field and to join forces. We are looking forward to meeting you at the next conference, to listen to your research talks and the resulting fruitful discussions and collaborations.

This book constitutes the refereed proceedings of the 14th International Conference on Tests and Proofs, TAP 2020, held as part of the 4th World Congress on Formal Methods 2020, Bergen, Norway, in June 2020. The 7 regular papers, 1 short paper and 2 demonstration papers presented in this volume were carefully reviewed and selected from 209 submissions. The TAP conference promotes research in verification and formal methods that targets the interplay of proofs and testing: the advancement of techniques of each kind and their combination, with the ultimate goal of improving software and system dependability.

This book constitutes the refereed proceedings of the 15th International Conference on Integrated Formal Methods, IFM 2019, held in Bergen, Norway, in December 2019. The 25 full papers and 3 short papers were carefully reviewed and selected from 95 submissions. The papers cover a broad spectrum of topics: from language design to verification and analysis techniques, to supporting tools and their integration into software engineering practice including both theoretical approaches and practical implementations. Also included are the extended abstracts of 6 "journal-first" papers.

Static analysis of software with deductive methods is a highly dynamic field of research on the verge of becoming a mainstream technology in software engineering. It consists of a large portfolio of - mostly fully automated - analyses: formal verification, test generation, security analysis, visualization, and debugging. All of them are realized in the state-of-art deductive verification framework KeY. This book is the definitive guide to KeY that lets you explore the full potential of deductive software verification in practice. It contains the complete theory behind KeY for active researchers who want to understand it in depth or use it in their own work. But the book also features fully self-contained chapters on the Java Modeling Language and on Using KeY that require nothing else than familiarity with Java. All other chapters are accessible for graduate students (M.Sc. level and beyond). The KeY framework is free and open software, downloadable from the book companion website which contains also all code examples mentioned in this book.