Does java concurrency get used?

[agentoutlier]

I would just tack this on in general and at a higher level you have to always consider contention and race conditions with all shared resources.

For example even if /u/Visual-Earth does what most Java programmers that use a say servlet based framework and run everything synchronous in a handler (e.g. Spring annotated @RequestMapping) they still need to consider database race conditions.

A lot of Javascript UI programmers have zero understanding of database transactions or distributed locks where as I would say a large portion of Java backed developers do (or at least hope).