title: Mono vs CompletableFuture
body: <p><code>CompletableFuture</code> executes a task on a separate thread ( uses a thread-pool ) and provides a callback function. Let's say I have an API call in a <code>CompletableFuture</code>. Is that an API call blocking? Would the thread be blocked till it does not get a response from the API? ( I know main thread/tomcat thread will be non-blocking, but what about the thread on which CompletableFuture task is executing? )</p>
  
  <p>Mono is completely non-blocking, as far as I know.</p>
  
  <p>Please shed some light on this and correct me if I am wrong.</p>