I worked at a bank and saw that pattern used in market connection middleware as well. It's really common, but since that stuff is all closed source it's hard to

I worked at a bank and saw that pattern used in market connection middleware as well. It's really common, but since that stuff is all closed source it's hard to point to a concrete example. (The thing was also optimized to reuse objects to allocate as little as possible... but a writeup from that team on an internal website said, basically, that Java GC was so efficient nowadays that it may not have been worth the extra maintenance effort and potential for bugs, in retrospect)