Does using the 'catch, when' feature make exception handling faster because the handler is skipped as such and the stack unwinding can happen much earlier as when compared to handling the specific use cases within the handler?
Both constructs (catch () being a syntax error, as sh4nx0r rightfully pointed out) behave the same in C#. The fact that both are allowed is probably something the language inherited from C++ syntax. , can throw objects that do not derive from System.Exception. In these languages, catch will handle those non-CLS exceptions, but catch (Exception) won't.
That output 'CommandNotFoundException' correctly. I vaguely remember reading elsewhere (though I couldn't find it again) of problems with this. In such cases where exception filtering didn't work correctly, they would catch the closest Type they could and then use a switch. The following just catches Exception instead of RuntimeException, but is the switch equivalent of my first example that ...
1622 I want to catch and log exceptions without exiting, e.g., ... I want to print the exact same output that is printed when the exception is raised without the try/except intercepting the exception, and I do not want it to exit my program.
r - How to use the tryCatch () function? - Stack Overflow
Is it safe to catch stack overflows? Can it leave objects in messy ...
In the second scheme, if the promise p rejects, then the .catch() handler is called. If you return a normal value or a promise that eventually resolves from the .catch() handler (thus "handling" the error), then the promise chain switches to the resolved state and the .then() handler after the .catch() will be called. So that's difference #2.