title: java.util.concurrent.TimeoutException: null after status 200 OK?
body: <p>I am presently developing a Java 11 Spring boot application.
  Within a CompletableFuture I am firing a load of REST requests to a webservice. Only one of them (randomly it seems) results in a TimeoutException though it is followed by a successful status 200 OK received response in the logging. Following the (anonymized) log entries:</p>
  <pre><code>[Thread-6] INFO  n.d.b.a.b.i.RESTInterceptor - Request              : &lt;url value&gt;?code=abcd&amp;begindatum=2018-10-01&amp;einddatum=2018-10-02
  [http-nio-8080-exec-1] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [/xxx] threw exception [Request processing failed; nested exception is java.util.concurrent.CompletionException: java.util.concurrent.TimeoutException] with root cause
  java.util.concurrent.TimeoutException: null
      at java.base/java.util.concurrent.CompletableFuture$Timeout.run(CompletableFuture.java:2792)
      at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
      at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
      at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
      at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
      at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
      at java.base/java.lang.Thread.run(Thread.java:834)
  [Thread-6] DEBUG n.d.b.a.b.i.RESTInterceptor - Response statuscode  : 200 OK
  [Thread-6] DEBUG n.d.b.a.b.i.RESTInterceptor - Response headers     : [X-Application-Context:&quot;yyyy&quot;, Cache-Control:&quot;no-cache, no-store, max-age=0, must-revalidate&quot;, Pragma:&quot;no-cache&quot;, Expires:&quot;0&quot;, Server:&quot;CD&quot;, X-Powered-By:&quot;Unknown&quot;, Content-Type:&quot;application/json;charset=UTF-8&quot;, Date:&quot;Tue, 06 Apr 2021 15:23:16 GMT&quot;, Connection:&quot;close&quot;, X-Frame-Options:&quot;SAMEORIGIN&quot;, X-XSS-Protection:&quot;1;mode=block&quot;, X-Content-Type-Options:&quot;nosniff&quot;]
  [Thread-6] INFO  n.d.b.a.b.i.RESTInterceptor - Response             : [{&quot;begindatum&quot;:&quot;1993-01-01&quot;,&quot;id&quot;:&quot;aaaaa&quot;,&quot;vanInstellingserkenningId&quot;:&quot;bbbbb&quot;,&quot;naarInstellingserkenningId&quot;:&quot;ccccc&quot;,&quot;soort&quot;:&quot;HIERARCHISCH&quot;,&quot;naarInstellingserkenning&quot;:{&quot;id&quot;:&quot;ddddd&quot;,&quot;type&quot;:&quot;ERKENDE_ONDERWIJSINSTELLING&quot;,&quot;code&quot;:&quot;abcd&quot;},&quot;vanInstellingserkenning&quot;:{&quot;id&quot;:&quot;kkkk&quot;,&quot;type&quot;:&quot;BEVOEGD_GEZAG&quot;,&quot;code&quot;:&quot;12345&quot;}}]
  </code></pre>
  <p>Is there someone having the same experience? I cannot see any difference in the successfully completed requests and the 'failing' one.</p>