Yes and No, variables, parameters and method return values also retain generic parameter information, this being available via reflection and to the compiler. It's object instances where this stuff is erased.
throws declarations follow a similar pattern, they exist in bytecode, but get ignored by the runtime and are lost in JIT compilation. The analogy breaks down a bit here, as methods aren't first class types, and can't exactly be instantiated. On 25 March 2011 15:38, Ricky Clarkson <[email protected]> wrote: > Throws clauses are not erased, they are present in the bytecode but ignored > by the runtime. You're confusing that with erasure, whereby objects don't > 'know' their type, only their class. > > On Fri, Mar 25, 2011 at 10:34 AM, Kevin Wright > <[email protected]>wrote: > >> >> >> On 25 March 2011 13:04, JodaStephen <[email protected]> wrote: >> >>> My objection to checked exceptions is I suspect slightly different to >>> some. >>> >>> In theory, they are a great idea. An extension to the static type >>> system (as such, its surprising that all exceptions in Scala aren't >>> checked!). The theory is that you write your code and force the user >>> of your API to actually think about the errors that might occur. >>> >> >> Not possible. Throws clauses are erased, just as collection elements are, >> and are only checked by the compiler and not the runtime (hence the ability >> to even write @sneakyThrows or to "chuck" them without requiring a >> RuntimeException wrapper) >> >> Checked exceptions are more of a shadow type system, not so much extending >> it as running alongside it. Essentially, they offer a sideband return >> channel. >> >> Given the availability of "Either", true pattern matching, and monadic >> comprehension in Scala, there's no need for this kind of hackery. An >> exception (or any other type) can simply be offered up as a possible >> alternative return value via the usual return mechanism. >> >> Unchecked exceptions can then be quite correctly reserved for things that >> are... well... exceptional! >> >> >> >>> However, after 15 years, all the evidence is that this fails the >>> usability requirement. The mass of developers (right up to Sun) are >>> clearly unable to *use* this feature in a useful and meaningful way. >>> Thats all - the entire total of the argument for me. >>> >>> Despite year after year of discussion, conference talks, forum >>> discussions, code reviews and much more, the Java community hasn't >>> managed to produce an agreed and successful use of the feature. >>> Examples in this case include all the catch and ignore, catch and >>> rethrow, adding of "Exception" to every single throws clause, >>> disagreement on how exception hierarchies should be structured, >>> arguments over whether a particular exception should be checked or >>> unchecked, and many more. >>> >>> Thus, no matter how good a feature is in theory, how useful it might >>> be, how its "just a matter of training" or "using it properly", the >>> absence of successful usage and the presence of unsuccessful usage >>> tells you all you need to know - its a failure. Usability is the only >>> criteria that matters. >>> >>> Stephen >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "The Java Posse" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]. >>> For more options, visit this group at >>> http://groups.google.com/group/javaposse?hl=en. >>> >>> >> >> >> -- >> Kevin Wright >> >> gtalk / msn : [email protected] >> <[email protected]>mail: [email protected] >> vibe / skype: kev.lee.wright >> quora: http://www.quora.com/Kevin-Wright >> twitter: @thecoda >> >> "My point today is that, if we wish to count lines of code, we should not >> regard them as "lines produced" but as "lines spent": the current >> conventional wisdom is so foolish as to book that count on the wrong side of >> the ledger" ~ Dijkstra >> >> -- >> You received this message because you are subscribed to the Google Groups >> "The Java Posse" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/javaposse?hl=en. >> > > -- Kevin Wright gtalk / msn : [email protected] <[email protected]>mail: [email protected] vibe / skype: kev.lee.wright quora: http://www.quora.com/Kevin-Wright twitter: @thecoda "My point today is that, if we wish to count lines of code, we should not regard them as "lines produced" but as "lines spent": the current conventional wisdom is so foolish as to book that count on the wrong side of the ledger" ~ Dijkstra -- You received this message because you are subscribed to the Google Groups "The Java Posse" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/javaposse?hl=en.
