Default number of threads in Spring boot 2.0 reactive webflux configuration

Question

While using Spring 5 reactive webflux with Spring boot 2.0, what's the default number of threads used to handle requests? How can I configure the number of threads used?

Answer 1

The default number of threads for request handling is determined by the underlying web server; by default, Spring Boot 2.0 is using Reactor Netty, which is using Netty's defaults (check out the EventLoopGroup documentation for that).

Spring Boot will soon allow you to customize that part (see #10418). In the meantime, you can provide your own ReactiveWebServerFactory bean and change that through the HttpServer configuration options (see this comment).