Hi Peter, > -----Original Message----- > From: Peter Levart <peter.lev...@gmail.com> > Sent: Freitag, 29. März 2019 16:44 > To: Lindenmaier, Goetz <goetz.lindenma...@sap.com>; 'Mandy Chung' > <mandy.ch...@oracle.com> > Cc: core-libs-dev@openjdk.java.net; maurizio.cimadam...@oracle.com; > hotspot-runtime-...@openjdk.java.net > Subject: Re: RFR(L): 8218628: Add detailed message to NullPointerException > describing what is null. > > > > On 3/29/19 4:36 PM, Peter Levart wrote: > > > > > > On 3/29/19 8:49 AM, Lindenmaier, Goetz wrote: > >> So I want to withdraw my claim that NPEs are thrown frequently. > >> Probably I was biased by my compiler construction background, > >> remembering NPE checks are all over the place in the code. > >> > >> But I think I can still keep the claim that the message is > >> printed rarely. > >> > >> I'll adapt the JEP saying something like this: > >> "While exceptions are supposed to be thrown rarely, i.e., only > >> In exceptional situations, most are swallowed without ever > >> looking at the message. Thus, overhead in getMessage() will > >> not fall into account." > > > > Is this really a realistic assumption? That NPE exceptions are mostly > > swallowed in most programs despite the fact that swallowing exceptions > > (and throwing them to control the flow) is an anti-pattern? Is > > majority of code really so badly written? I would expect that most > > programs contain an exception handler of some kind that at least logs > > all unexpected exceptions. > > > > I think JDK should assume that NPEs are not frequent in most well > > written programs. Because in well written programs all unexpected > > exceptions are at least logged somewhere and this alone guarantees > > that programs are eventually "fixed" to not throw them frequently... > > > > Regards, Peter > > So I would say that there are two kinds of programs (which kind is in > majority doesn't matter): > > a - programs that throw and catch exceptions for exceptional situations > only (i.e. non frequently) - they also print the exceptions' messages > b - programs that throw and swallow exceptions frequently, but they > mostly don't print their messages > > In either case .getMessage() is not called frequently for kind (a) and > hopefully also for kind (b). > > Regards, Peter Hi,
I agree with this, and my numbers show that the message is not printed frequently in any case. Best regards, Goetz.
