throws clause is used to declare an exception and throw keyword is used to throw an exception explicitly. If we see syntax wise then throw is followed by an instance variable and throws is followed by exception class names. The keyword throw is used inside method body to invoke an exception and throws clause is … Read more
It is clearly a compiler bug, and it was introduced in C# 3.0 — right around the time that I heavily refactored the reachability checker. This is probably my bad, sorry. The bug is completely benign; basically, we just forgot a case in the warning reporter. We generate the reachability information correctly; as others have … Read more
Yes. The exception is active until it’s caught, where it becomes inactive. But it lives until the scope of the handler ends. From the standard, emphasis mine: §15.1/4: The memory for the temporary copy of the exception being thrown is allocated in an unspecified way, except as noted in 3.7.4.1. The temporary persists as long … Read more
For more detailed reasoning, see: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3051.html As expressed in the national body comment above, exception specifications have not proven useful in practice. There are numerous discussions of the problems with exception specifications in C++ (see, e.g., [Sutter02], [Boost03]), but the main issues are: Run-time checking: C++ exception specifications are checked at runtime rather than at … Read more
I would recommend you never throw NullPointerException by yourself. The main reason not to do this, as Thorbjørn Ravn Andersen says in a comment below, is that you don’t wan’t to mix ‘real, bad NPEs’ with NPEs thrown intentionally. So, until you’re confident that you’re able to recognize ‘valid’ NPE, I’d recommend to use IllegalArgumentException … Read more
Exception specifiers were deprecated because exception specifiers are generally a terrible idea. noexcept was added because it’s the one reasonably useful use of an exception specifier: knowing when a function won’t throw an exception. Thus it becomes a binary choice: functions that will throw and functions that won’t throw. noexcept was added rather than just … Read more
The difference between ‘throw new Error’ and ‘throw someObject’ in javascript is that throw new Error wraps the error passed to it in the following format − { name: ‘Error’, message: ‘String you pass in the constructor’ } The throw someObject will throw the object as is and will not allow any further code execution … Read more
Declarations of var variables get hoisted – the variable name initialization gets hoisted to the top of the containing function (or, if no function, to the top of the outer block). So var withVar = (function() {throw ‘error!’})() is parsed by the interpreter as var withVar; withVar = (function() {throw ‘error!’})() The same is not … Read more
Throwing twice in the same method is probably a special case – I’ve not been able to create a stack trace where different lines in the same method follow each other. As the word says, a “stack trace” shows you the stack frames that an exception traversed. And there is only one stack frame per … Read more
Exception specifiers were deprecated because exception specifiers are generally a terrible idea. noexcept was added because it’s the one reasonably useful use of an exception specifier: knowing when a function won’t throw an exception. Thus it becomes a binary choice: functions that will throw and functions that won’t throw. noexcept was added rather than just … Read more