Robin wrote:Also, RE: Java: the core language may not be too slow, but many of the standard library things (Swing, anyone?) certainly are. And you have to take those in consideration, because Java is nothing without its stdlib.
Yes and no - Swing may be part of the standard library, but Java sees much of its use in environments that don't need a GUI - Apache Tomcat, for instance. Or everyone's favorite trivia robot, Watson, which comprises over 600,000 lines of Java (and over 400,000 lines of C++). Or a whole lot of enterprise-level software. And in these situations, which are nothing if not performance-critical, Java holds up just fine. Pretty much anything graphics-related, particularly Swing, is painfully slow, but otherwise Java is actually highly performant - the "Java is too slow for anything important" meme is very much out-of-date.
kikito wrote:The search architecture functionality was moved to java. The rest is still ruby.
Actually, the back-end stuff was switched to Scala a couple of years prior to that post. Twitter's removed Ruby from their stack entirely.