[tsimionescu]

I didn't claim that all functions are either correct or throw an exception in Java. I said that UB doesn't exist in Java, in the sense of a Java program that compiles, but for which no semantics are assigned and the programmer is not allowed to write it. All situations that are UB in C or C++ are either well-defined in Java (signed integer overflow, non-terminating loops that don't do IO/touch volatile variables), many others throw exceptions (out of bounds access, divide by 0), and a few are simply not possible (use after free). Another few are what the C++ standard would call "unspecified behavior", such as unsynchronized concurrent access.

And yes, it's the programmer's job to make sure functions are called in their domain of apllication. But it doesn't help at all when the compiler prunes your code-as-written to remove flows that would have reached an error situation, making debugging much harder when you accidentally do call them with illegal values.