I think the same problem also appears in StringBuffer and has been remarked on repeatedly over the years, e.g.
http://osdir.com/ml/java.findbugs.general/2007-02/msg00068.html Michael Kay Saxonica m...@saxonica.com +44 (0) 118 946 5893 On 16 Aug 2014, at 20:17, Louis Wasserman <lowas...@google.com> wrote: > There are indications this bug has actually occurred in released JDK code > before (!!): > > http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/7-b147/java/util/Formatter.java#2882 > > To give credit where credit is due, I reported the potential for this issue > to Eddie after seeing it on StackOverflow at > http://stackoverflow.com/q/25167015. > On Aug 16, 2014 5:39 AM, "Andrew Thompson" <lordpi...@me.com> wrote: > >> I've encountered bugs in production code due to this surprise. >> >> A good thing to fix. >> >>> On Aug 16, 2014, at 1:38 AM, Jeremy Manson <jeremyman...@google.com> >> wrote: >>> >>> No love from core-libs-dev? It's backwards-incompatible, but in a way >> that >>> would unbreak existing broken code. Might be a worthwhile cleanup. >>> >>> Jeremy >>> >>> >>>> On Fri, Aug 8, 2014 at 1:53 PM, Eddie Aftandilian <eaf...@google.com> >> wrote: >>>> >>>> Hi all, >>>> >>>> We recently realized that calling new StringBuilder(char) does not do >> what >>>> you would think it does. Since there is no char constructor defined, >> the >>>> char is widened to an int and the StringBuffer is presized to the >>>> character's encoded value. Thus code like this prints an empty string >>>> rather than the expected "a": >>>> System.out.println(new StringBuilder('a')); >>>> >>>> Would it be possible to add a char constructor to StringBuilder to >> prevent >>>> this problem? I understand this would change the behavior of any code >> that >>>> is currently doing this, but it's hard to imagine anyone doing this >>>> intentionally. Of the ~20 instances we found in Google's codebase, all >>>> were bugs. What is your policy on making changes like this where (a) it >>>> will cause a change in behavior, but (b) the currently behavior is >> clearly >>>> wrong? >>>> >>>> If you're willing to take the change, I'd be happy to send a patch. >>>> >>>> Thanks, >>>> Eddie >>>> >>
