title: Why is tomcat going to 200+ threads with Spring WebFlux?
body: <p>I am doing a POC with Spring WebFlux on Tomcat. The stack is totally reactive and using Spring Reactor and Reactive Couchbase. </p>
  
  <p>When I added load on the System, I saw that the number of threads in JVisualVM increased to 200+. Basically, <strong>reactor-http</strong> threads were limited, about 4 as expected. </p>
  
  <p>But <strong>http-nio-exec</strong> threads jumped to around 200. 
  If I run with Netty instead of Tomcat the the number of threads is limited about 30 only. </p>
  
  <p>Can some one explain why Tomcat is spinning up so many threads with a Reactive Stack?</p>