BZ #9: Verification should complete successfully before class initialization

Status fields:

creation_ts:2005-07-22 01:02
This is probably just pure pedantry, but the JVM specification says (section 5.4.1):

"A class or interface must be successfully verified before it is initialized."

However, some verification failures - such as out-of-range targets of branches
in a tableswitch - are reported by cacao only after class initialization is
complete. Indeed, sometimes after some methods in the class have already been

I don't know if this matters "in the real world". I just noticed the discrepancy
and I thought I'd point it out, just in case it turned out to be important.

Comment #1 by on 2005-11-19 14:27:07

This is one of the cases where the spec contradicts itself:

[from Section 4.9.1 The Verification Process]

    Pass 4:
    For efficiency reasons, certain tests that could in principle be performed
    in Pass 3 are delayed until the first time the code for the method is
    actually invoked. In so doing, Pass 3 of the verifier avoids loading class
    files unless it has to.

In fact it's not only for efficiency but correctness. There is a lot of code
out there that assumes that only code which is actually executed is verified.
(And only *when* it is executed for the first time.)

Comment #2 by on 2005-11-19 14:37:45

Well, to address the example of out-of-range targets: This actually
*could* be performed right after loading without sacrifycing
correctness. Since verification, however, cannot be completed anyway, I do
not think it would make sense. This check is also delayed for "efficiency
reasons", since we do not want to parse code that may never be executed.