Twitter has now moved its entire search stack from Ruby-on-Rails to Java.

That's a big shift. Twitter moved its back end message queue from Ruby to Scala, a Java platform in the 2008-2009 time frame. The move was attributed to issues with reliability on the back-end.

This latest move makes the shift pretty much complete. At Twitter, Ruby is out of the picture.

Twitter explains the change on its engineering blog:

Last week, we launched a replacement for our Ruby-on-Rails front-end: a Java server we call Blender. We are pleased to announce that this change has produced a 3x drop in search latencies and will enable us to rapidly iterate on search features in the coming months.

Does this mean that Java is better than Ruby for services with heavy loads?

Ganeshji Marwaha, director at Triomatrix Webservices, says it all depends:

Wow, that is quite an achievement. Could this mean that Java is a better platform than Rails for high scalability needs? Even if that is the case, for simpler scenarios, the beauty of RoR out-weighs Java's performance.

They say that this change will enable them to rapidly iterate on search features in the coming months. That along with the news that Twitter has hired 25 more employees kinda tells that Java's code base is practically more maintainable than equivalent Ruby code - at least when the code base is huge and the team size is large. Or that could mean that this time they really put a lot of thought into designing a maintainable system than when they started out. But for smaller team size and code base, RoR is still an unbeaten champion.

You can read the full account about the new search capabilities with Java on the Twitter blog post. It goes into detail about the changes and the benefits that it is seeing with the switch.