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CodeHero

Code conversion, pair by pair

Java to Perl

The same routine, written by hand in Java and in Perl. It is here so you can see what changes and what does not before anyone quotes you anything.

Before · Java

public static BigDecimal interest(BigDecimal balance, BigDecimal rate) {
    return balance.multiply(rate).setScale(2, RoundingMode.HALF_UP);
}

What it becomes · Perl

sub interest {
    my ($balance, $rate) = @_;
    return sprintf('%.2f', $balance * $rate);
}
One routine: a balance times a rate, rounded to the cent. Written by an engineer in both languages, so you can read what the target actually looks like.
Below is one routine in both languages. On a real system the same move runs across the whole tree at once — our platform reads every language in it in parallel, builds the dependency graph, and an engineer cuts the boundaries. A million lines is the normal size of that job, and it finishes inside thirty days.

What this looks like on your whole system

On your actual codebase the same move answers the questions a pair of files cannot: which files nothing calls any more, which batch job writes the record another one reads at 02:00, and whether the rewritten version still produces the numbers your auditors saw last month. The assessment comes back with all three, in three to five days.