code: public JettyBootstrap joinServer() throws JettyBootstrapException {
          try {
              if (isServerStarted()) {
                  LOG.debug("Joining Server...");
  
                  server.join();
              } else {
                  LOG.warn("Can't join Server. Not started");
              }
          } catch (InterruptedException e) {
              throw new JettyBootstrapException(e);
          }
  
          return this;
      }
docs: Blocks the calling thread until the server stops.
  
  @return this instance
  @throws JettyBootstrapException
  if an exception occurs while blocking the thread