We see that surprisingly rarely because the completely clueless tend to get saved by identity hashcode/equals. (and the lazy, and often even the pragmatic) Wet

We see that surprisingly rarely because the completely clueless tend to get saved by identity hashcode/equals. (and the lazy, and often even the pragmatic) Wether or not you get to see code falling into the mutable hash trap probably depends a lot on culture and the hiring process/environment. Do people feel empowered to do the right thing? Or free to take whatever easy path that works for them? Or are they pressured/incentivized to aim for some superficial appearance metrics?