$Id: TODO.JustIce 152844 2003-01-28 18:03:18Z enver $
"TODO" list for JustIce, the Java Class File Verifier by Enver Haase.
- JustIce uses object generalization during pass 3b, as supposed by
Sun. However, there are better methods such as the idea proposed by
Staerk et al.: using sets of object types. JustIce may reject code
that is not rejected by traditional JVM-internal verifiers for this
reason. The corresponding checks all have some "TODO" tag with an
explanation; they're all in the 'InstConstraintVisitor.java' file.
Users encountering problems should simply comment them out (or
uncomment them) as they like. The default is some setting that works
well when using
$ java org.apache.bcel.verifier.TransitiveHull java.lang.String
meaning there are no rejects caused by the above problem in a lot of
usual classes.
- There are a few bugs concerning access rights of referenced methods
and probably fields. The tests for access rights that Sun defines
should happen in pass four (which JustIce performs during pass 3a) are
unintentionally omitted. This also happened to Sun and IBM with some
of their version 1.3 JVMs. Thanks Markus Dahm.
- There are bugs because of an ambiguity in the Java Virtual Machine
Specification, Second Edition. These have to do with inheritance: A
method invocation like MyObject::equals(Object) is considered illegal,
if MyObject has no overriding definition of equals(Object). Sun
clarified this issue via electronic mail: the invocation is legal,
because MyObject inherits the member function equals(Object) from
Object::equals(Object). The search algorithms don't seem to be trivial
because interfaces can not only specify methods, but also declare
fields. Also, access modifiers have to be honoured (see above).
- It is not verified if classes that propose they would implement an
interface _really_ implement all the methods.
- It is not verified that interfaces are actually tagged 'abstract'.
- The InstructionContext.getSuccessors() method may return the same
successor more than one time. For performance reasons the ControlFlow-
Graph.InstructionContextImpl class should return an array where the
successors are pairwise disjoint. It should also be cached so that we
don't have to do this calculation every time.
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