[Clirr-devel] adding methods to interfaces

[Simon K. <si...@ec...>]

Hi,

In MethodSetCheck, the reportMethodAdded method uses:
      final Severity severity = 
	!newClass.isInterface() && 
	(newClass.isFinal() || !newMethod.isAbstract())
                ? Severity.INFO
                : Severity.ERROR;


This means that adding a method to an interface is reported as an ERROR.
However the java spec section 13.5.3 says:

<quote>
Adding a method to an interface does not break compatibility with
pre-existing binaries
</quote>

I've tested this, and this seems to be correct: there will not be a
*linktime* error reported under any circumstances. However if I have
code which implements the old interface, and I then pass this object to
code that tries to invoke a new method, an AbstractMethodError runtime
exception occurs.

So I think that this should be a WARNING, not an error. What do you
think?

-------------------------------

I'm also somewhat puzzled by the remainder of the ternary expression
too.

Adding an abstract method to a class is indeed a problem, because
subclasses can exist which don't have that method. But like the
interface issue, I think this is a WARNING (runtime problem) rather than
an ERROR (linktime problem).

And why is it ok to add an abstract method to a final class? Final
classes are never allowed to be abstract, so this shouldn't be possible
as far as I know..

Regards,

Simon