So it's not that the optimization fails but there is no optimization on them yet.
I do see the .append("x") case will be easy to deal with, but it looks like historically javac has not been a place to do many optimizations. It mostly converts the java source to byte codes in a 1-to-1 mapping and let VM do whatever it wants (to optimize). When you talked about compiling multiple concatenation into using a single StringBuilder, it's more like choosing the correct implementation rather than an optimization. I don't expect to see big change on this in the near future, so shall we go on with the current enhancement? Thanks Max On Aug 29, 2014, at 2:17, Ulf Zibis <ulf.zi...@cosoco.de> wrote: > I mean: > It does not output byte code that only uses a single char array to compose > the entire String in question. > With "optimization fails", I also mean, there is used an additional > "StringComposer" e.g. another StringBuilder or a StringJoiner in addition to > the 1st StringBuilder. > > -Ulf > > Am 27.08.2014 um 14:02 schrieb Pavel Rappo: >> Could you please explain what you mean by "javac optimization fails" here? >> >> -Pavel >> >> On 27 Aug 2014, at 10:41, Ulf Zibis <ulf.zi...@cosoco.de> wrote: >> >>> 4.) Now we see, that javac optimization fails again if StringBuilder, >>> concatenation, toString(), append(String), append(Collection) etc. and >>> StringJoiner use is mixed. >> >