Exercises with JML and ESC/Java3
Bag and Amount exercises
For these exercises, you should specify the two classes
with JML and run ESC/Java2 to verify these specifications.
Simply put, you run ESC/Java2 on these files and if the tool
produces some warning, you
to make the warning go away. You have to use your own best judgement
to choose between these two options, but there are some deliberate bugs
in the code for you to detect, with the help of the tool.
Note that there are some deliberate errors in the code for you to find.
- either add annotation to the code (eg to document
invariants, preconditions, or postconditions)
- or fix bugs in the code
For Amount.java you must also try to formalise the informal invariant
that is discussed in the file as a JML invariant, which should reveal
some more problems in the code.
In the end, ESC/Java2 should run without any complaints on the annotated code.
ESC/Java2 complains (among other things) if it thinks a runtime
exception may occur, say a NullPointerException, so if ESC/Java2 runs
without complaints this means it has verified that no runtime exceptions
More detailed instructions are given in the Java files. Read these!