> The "well I guess we gotta replace this with a C++ solution" sentiment smacks of poor software engineering practice, despite the results.
On the flip side, recognizing when you are not efficiently using your time to solve a problem with the current approach and deciding to switch to another one is what I would consider a vital part of good software engineering, and also one of the hardest things to become good at without a lot of experience.
I'm not sure that's the case here, but I don't doubt it's possible they could easily have wasted more time testing and tweaking Java than it took to implement this solution. Whether that's how it would have (or possible even did to a degree) played out is an open question.