Formal Methods for Software Development TDA294/DIT271, LP1, HT2019



We provide an online interface to some of the tools used in the course, to avoid installation problems.

  • Notes on saving
    • The web-interface does not save your files. To save your progress, copy the content of the editor into a file local on your machine (or save it by pressing Ctrl+S)!
  • Spin (Open Web-Interface)
    • In the top-left corner you find a collection of examples and Promela files used in the course, as well as a cheat sheet to the most used Promela syntax.
    • You can create a file by either choosing one from the collection of examples, or by clicking the (+) button above the editor.
    • You can press Ctrl+S in an opened tab to save that tab to your local machine.
    • The control panel on the right allows you to run simulations and verifications on the file that is in the currently opened tab (programs with multiple files are not supported).
    • The first group of options displays events that are printed during simulations and guided runs. Note that if 'Statements' is not selected almost no information will be printed. These options apply to both the simulation as well as running the generated trail of verification.
    • It is recommended to use the 'Stop after ...' option when running simulations that print all statements, otherwise your browser might take a long time for displaying the output.
    • For verification, select the right mode (Safety, Acceptance / Liveness, Non-progress) and specify the name of the named LTL formula in the currently opened Promela file that you want to verify. If a counter-example is found and 'Run generated trail' is selected the trail of the counter-example is printed at the bottom of the output.
    • The timeout for simulations is set to 1 second; for verification it is set to 30 seconds.
  • OpenJML (Open Web-Interface)
    • In the top-left corner you find a collection of example Java files and those used in the course.
    • You can create a file by either choosing one from the collection of examples, or by clicking the (+) button above the editor.
    • By clicking the 'Syntax' button OpenJML is run to check that your JML annotations use correct syntax.
    • By clicking the 'ESC' button OpenJML runs an Extended Static Check, using Yices 2 as its back-end, to statically find violations of your JML specification.
    • You can hover over the warning / error markers on the left-hand side to see the output of OpenJML.

Promela, Spin, jSpin, LTL


  • We recommend to use a special built of the KeY system which was compiled for this course. It is the "fat JAR" file linked here. There are various ways to execute the JAR file, which depend on your browser configuration and operating system. In any case, you need Java RE (runtime environment) on your machine. We recommend Java 11 or higher, but it may also work with lower versions.
    • Download the file and execute it (possibly after making it executable), by double click or via the command line: java -jar <pathToFile>
    • Depending on your browser set-up, you might be able to run the JAR directly from the browser, by double clicking the link.
  • The KeY project website.
  • There is a book on the KeY approach and system called Deductive Software Verification - The KeY Book. See Course Literature. In particular, the book features:
    • "Formal Verification with KeY: A Totorial" (chapter 16)
    • "Using the KeY Prover" (chapter 15)
  • Note that the KeY version recommended above is not 100% compliant with the KeY book, as many improvements were made after the book was written. For more compliant versions, we refer to download pages of the KeY project website.


  • We have created an online interface to OpenJML (including static checking with Yices2) to avoid installation problems.
  • The latest version of OpenJML can be found on their website (direct link here).
  • Within the directory where you extracted openjml.jar, run the command
    java -Xbootclasspath/p:openjml.jar -jar openjml.jar -noInternalSpecs path_to_file
  • If you cannot run java 1.7, we have a local copy of an older release that still supported 1.6 here.
  • OpenJML allows you to compile to a bytecode (.class) file with inlined run-time assertion checks on your invariants, pre- and post-conditions. Try this for example with this file. Compile using:
    java -Xbootclasspath/p:openjml.jar -jar openjml.jar -rac -noInternalSpecs path_to_file
    (note the extra -rac flag). For Java 1.6, use instead:
    java -Xbootclasspath/p:openjml.jar -jar openjml.jar -rac -source 1.6 -target 1.6 -noInternalSpecs path_to_file
    Then run the program with:
    java -classpath ':*' JMLTest 12
    Where 12 is the input to the program. You can try different inputs and see how the assertions can be triggered.

W. Ahrendt, Sep 27, 2019