In production Java has a lot of upside. Compared to ruby or python it is screaming fast. Twitter has moved large portions of their app to java from rails because of this.
The reason why interpreted languages are hot with startups and why twitter was originally built on rails is the speed you get in development. Also production speed differences are being offset by cheaper faster hardware.
If you hit twitter or facebook scale issues and need more of a speed bump than you can get by throwing more boxes at the problem. Congratulations you've won and if you built on ruby you can go from mri to jruby and get all the java production speed without giving up the ruby development speed.
Twitter moved to Scala, not Java.
Java can be valuable if you really get into it, to a point where you begin to understand the internals of the JVM, because that is not going anywhere soon.
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In production Java has a lot of upside. Compared to ruby or python it is screaming fast. Twitter has moved large portions of their app to java from rails because of this.
The reason why interpreted languages are hot with startups and why twitter was originally built on rails is the speed you get in development. Also production speed differences are being offset by cheaper faster hardware.
If you hit twitter or facebook scale issues and need more of a speed bump than you can get by throwing more boxes at the problem. Congratulations you've won and if you built on ruby you can go from mri to jruby and get all the java production speed without giving up the ruby development speed.
Twitter moved to Scala, not Java. Java can be valuable if you really get into it, to a point where you begin to understand the internals of the JVM, because that is not going anywhere soon.