Replace concat String to append in StringBuilder parameters

[Ulf Zibis]

Am 11.08.2014 um 16:33 schrieb Pavel Rappo:
> Unfortunately, neither java.util.StringJoiner nor String.join have perfect (but who has?) APIs. So it's up to us to figure out the best way of joining elements.

Maybe remember my thoughts from here:
http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-April/016172.html
http://mail.openjdk.java.net/pipermail/core-libs-dev/2014-January/024761.html

Would it be possible to inherit StringJoiner from StringBuilder in some way?
Then a mixture of concatanation, StringBuilder and StringJoiner after Javac would end up in one 
StringBuilder instance. We also could profit from StringJoiners initial capacity capability.

-Ulf