title: Call Rest API by Spring RestTemplate within a @Async method
body: <p>As I know, Spring <em>RestTemplate</em> is synchronous and blocks the thread until the web client receives the response, and Spring <em>WebClient</em> is asynchronous and non-blocking.</p>
  <p>But what if we call an API using <em>RestTemplate</em> within an <em>@Async</em> annotated method?</p>
  <p>Does it block the new thread created by <em>@Async</em>?</p>
  <p>Finally, what's your suggestion for the async call of Rest APIs (without <em>WebClient</em> because I'm using Spring version older than 5).
  Thanks</p>