Featherweight Java A Minimal Core Calculus for Java and GJ
نویسندگان
چکیده
Several recent studies have introduced lightweight ver sions of Java reduced languages in which complex fea tures like threads and re ection are dropped to enable rigorous arguments about key properties such as type safety We carry this process a step further omitting almost all features of the full language including inter faces and even assignment to obtain a small calculus Featherweight Java for which rigorous proofs are not only possible but easy Featherweight Java bears a similar relation to full Java as the lambda calculus does to languages such as ML and Haskell It o ers a similar computational feel providing classes methods elds inheritance and dynamic typecasts with a semantics closely follow ing Java s A proof of type safety for Featherweight Java thus illustrates many of the interesting features of a safety proof for the full language while remaining pleasingly compact The syntax type rules and opera tional semantics of Featherweight Java t on one page making it easier to understand the consequences of ex tensions and variations As an illustration of its utility in this regard we extend Featherweight Java with generic classes in the style of GJ Bracha Odersky Stoutamire and Wadler and sketch a proof of type safety The extended system formalizes for the rst time some of the key features of GJ Subject areas theoretical foundations language de sign and implementation
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