Hacker News Reader

It really depends on the developers writing the application, but in my humble opinion Java and Swing are far better than Electron in terms of responsiveness to user interactions.

Java is unbeatable for "enterprise logic" though..

the primary java app I use is InteliJ suite and it seems as responsive/fast as any other app I use. Are they doing anything particularly unique?

IntelliJ is 20yo old app, with lots of resources invested, they likely have many non-trivial optimizations implemented and do not represent vanilla java experience.