Fully automated? I don't think so, and it falls apart suprisingly quickly. To give an example: All variables (well, in "classical COBOL" at least) are global v

Fully automated? I don't think so, and it falls apart suprisingly quickly. To give an example: All variables (well, in "classical COBOL" at least) are global variables. Since memory is constrained, a really common idiom is to have great swathes of punned, overlayed variables; in C terms it would be unioned structs. Subroutine A would have a var A-TEMPS divided into A-TEMP-VAR1 and A-TEMP-VAR2. Since routine B isn't on the same call path, that _same area_ could be also divided into B-TEMPS, B-TEMP-X, B-RESULT, and C-MOVEIN (because hey, code got changed). When you port this mess to Java you can (a) emulate unions with mind-boggling complex , huge, and fragile idioms, (b) tease out the actual code flow graphs and intent, or (c) some combination. And no, automated doesn't go very far for (b); although the computer might be able to figure out that March doesn't have a leap day and so this path won't execute because of that, it _is_ the end of a quarter and so has an artificial closing-day tacked on _if_ this is for subsidiary Foo, but not Bar because they have a 0-day on the following month. Too many combinations to exhaustively compute, and requires a lot of human smarts to prune possibilities.