[spullara]

If there is no way to break the ambiguity the compilation will fail and you will have to override that method (in 8.4.8.4 of the spec). You can use IA.super or IB.super to call one of the default methods if one of them works for you and you don't need your own bespoke implementation.

[mbel]

Thanks for clarifying; although I don't really like this feature, compilation failure seems to be the best solution (and well I guess I should have RTFM to begin with, sorry).