As someone who dealt with a ton of Spring in the recent past, I completely disagree.
First of all, thread pools are part of the standard library. Spring adds little to no value on top of it.
Second, reinventing some of that stuff is absolutely worthwhile, because Spring's library design/implementation is not very good.
Finally, when I had the opportunity to start a new Java project, I opted to not use Spring. I finally had a server that started up fast, took less code than a Spring project, was easily navigable in an IDE, and whose code was generally easier to follow. It was also easier to write tests for.
One thing I learned is that people seem to underestimate just how thin Spring's abstractions are over stuff in the library, servlets, etc. Most of what Spring does is wrap things in a bean interface so they can be used with DI (which is something I’ve never found any value in).
