20 years go while programming java, I was struck by how simple and universally useful it is, to have any method that throws exceptions to be forced to declare them in the method signature, and all callers are then forced to either pass on the exception or provide a try catch that deals with it, making it almost impossible to have programd crash from un handled exceptions.

It was perfect, except for all the crashes from null variables back then. And my current favourite language Dart cuts null pointers by 99.99 percent by giving you null safety.

Checked exceptions and null safety, and suddenly programs crash like 90 percent less.

Now we must just figure out how to systematically eliminate index-out-of-bounds too, then 98 percent of program crashes are gone. All without writing unit tests and other costly rituals.

Just good language design.