title: Jsoup executing concurrently throws UnknownHostException
body: <p>I try to run Jsoup (version 1.11.2) in parallel with this code:</p>
  
  <pre><code>public class JsoupParallelRunner {
  
  private static String[] urls = { ... some URLs ...}
  
  public static void main(String... args) {
      ExecutorService executor = Executors.newFixedThreadPool(10);
  
      for (String url : urls) {
          executor.execute(() -&gt; {
              try {
                  Connection c = Jsoup.connect(url);
                  Connection.Response r = c.execute();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          });
      }
  }
  </code></pre>
  
  <p>But if I use more than 6 parallel threads in the <code>FixedThreadPool</code> it throws a <code>java.net.UnknownHostException</code> in the <code>execute()</code> method of Jsoup. Below 6 there are no problems.</p>
  
  <p>According to <a href="https://stackoverflow.com/questions/13445589/jsoup-thread-safety">jsoup thread safety</a> Jsoup is thread-safe. </p>
  
  <p>If it is of any help: my CPU has 2 cores (4 virtual).</p>
  
  <p><strong>Update</strong>: It seems to be an issue of my computer only. I tried it on two other computers (same Java version, same Jsoup version) and there it worked.</p>
  
  <p><strong>Update 2</strong>: It seems to be an issue of my laptop in a certain network. I tried it with this laptop at my home network - and there it worked. Back to work - same problem. Everything else network related seems to work (Browser, ssh etc.). I guess it is some weird network issue and has nothing to do with Jsoup.</p>