Supported Java Features
Java is a very complex language which massively evolved over the time. KeY does not support all Java features. Some of those, like floating-point arithmetic, are in principle hard to handle from a theorem-proving point of view; others, like Generics and Lambdas, could be considered in future versions of the system. The following (incomplete) table gives an overview about the state of selected Java features in the current KeY version. Features shaded in green are supported, those in red are unsupported; features in yellow are in principle not supported, but can be treated with restrictions by a workaround supplied by KeY. A list of supported JML features is available here.Feature | State |
---|---|
Basic Java 1.2 features | KeY supports Integer arithmetic (for both mathematical Integers and actual Integer types with overflows), Strings, inheritance, dynamic dispatch, loops, recursion, … |
Enhanced “for” loops | Supported. |
Library methods | KeY will throw an error when you use libraries the code of which is not in KeY’s classpath. However, we have a plugin in our eclipse extension which can create stubs with default contracts for library methods such that you can directly start proving properties about your code, or manually refine the stub specifications before. |
Generics | Unsupported; However, a tool to statically remove Generics from the code can be downloaded here. |
Floating point types | Unsupported. |
Multithreading | Unsupported. |
try-with-resources and multi-catch (both Java 7) | Unsupported. |
Java 8 features (lambdas etc.) | Unsupported. |
Tutorials
Video Tutorial: Interactive Verification with the Symbolic Execution Debugger (SED)
Video Tutorial: Proof Attempt Inspection with the Symbolic Execution Debugger
Formal Verification with KeY: A Tutorial (2016)
By Bernhard Beckert, Reiner Hähnle, Martin Hentschel and Peter H. Schmitt Book chapter of the KeY book. This chapter gives a systematic tutorial introduction on how to perform formal program verification with the KeY system. It illustrates a number of complications and pitfalls, notably programs with loops, and shows how to deal with them. After working through this tutorial, you should be able to formally verify with KeY the correctness of simple Java programs, such as standard sorting algorithms, gcd, etc. Find this tutorial on SpringerLinkNote: The following tutorials may require older versions of KeY.
Verifying Object-Oriented Programs with KeY: A Tutorial (2007)
By Wolfgang Ahrendt, Bernhard Beckert, Reiner Hähnle, Philipp Rümmer, and Peter H. Schmitt. Abstract. This paper is a tutorial on performing formal specification and semi-automatic verification of Java programs with the formal software development tool KeY. This tutorial aims to fill the gap between elementary introductions using toy examples and state-of-art case studies by going through a self-contained, yet non-trivial, example. It is hoped that this contributes to explain the problems encountered in verification of imperative, object-oriented programs to a readership outside the limited community of active researchers. Download this tutorial.KeY: The Sequent Calculus of the KeY Tool (2015)
Tutorial at CADE-25 by Reiner Hähnle and Peter H. Schmitt You can download part I and part II of the slides of this tutorial as well as the corresponding KeY proofs.Relevant blog posts




Literature
2018
Modular, Correct Compilation with Automatic Soundness Proofs Inproceedings
In: Margaria, Tiziana; Steffen, Bernhard (Ed.): Leveraging Applications of Formal Methods, Verification and Validation. Modeling, pp. 424–447, Springer International Publishing, Cham, 2018, ISSN: 0302-9743.
2017
Verifying OpenJDK's Sort Method for Generic Collections Journal Article
In: Journal of Automated Reasoning, 2017, ISSN: 1573-0670.
A New Invariant Rule for the Analysis of Loops with Non-standard Control Flows Inproceedings
In: Polikarpova, Nadia; Schneider, Steve (Ed.): Integrated Formal Methods - 13th International Conference, IFM 2017, Turin, Italy, September 20-22, 2017, Proceedings, pp. 279–294, Springer, 2017.
2016
An Empirical Evaluation of Two User Interfaces of an Interactive Program Verifier Inproceedings
In: Proceedings of the 31st IEEE/ACM International Conference on Automated Software Engineering, pp. 403-413, ACM, Singapore, Singapore, 2016, ISBN: 978-1-4503-3845-5.
The Interactive Verification Debugger: Effective Understanding of Interactive Proof Attempts Inproceedings
In: Proceedings of the 31st IEEE/ACM International Conference on Automated Software Engineering, pp. 846–851, ACM, Singapore, Singapore, 2016, ISBN: 978-1-4503-3845-5.
Integrating Symbolic Execution, Debugging and Verification PhD Thesis
Technische Universität Darmstadt, 2016.
A General Lattice Model for Merging Symbolic Execution Branches Inproceedings
In: Ogata, Kazuhiro; Lawford, Mark; Liu, Shaoying (Ed.): Formal Methods and Software Engineering - 18th International Conference on Formal Engineering Methods, ICFEM 2016, Tokyo, Japan, November 14-18, 2016, Proceedings, pp. 57–73, Springer International Publishing, 2016.
Dynamic Dispatch for Method Contracts Through Abstract Predicates Journal Article
In: Trans. Modularity and Composition, vol. 1, pp. 238–267, 2016.
Darmstadt University of Technology, Germany, 2016.
2015
Dynamic Dispatch for Method Contracts through Abstract Predicates Inproceedings
In: Proceedings of the 14th International Conference on Modularity, MODULARITY 2015, Fort Collins, CO, USA, March 16 - 19, 2015, pp. 109–116, ACM, 2015.