code: @Override
      public DynamicVirtualHost getVirtualHost(String targetHost) throws WebAppHostNotFoundException {
          // Should never happen: but NPEs are ugly.
          if (vhostManager == null)
              return null;
  
          return vhostManager.getVirtualHost(targetHost, this);
      }
docs: Return a dynamic virtual host managed by the VirtualHostManager.
  The virtual host will be created on first request (whether or not there
  is a backing VirtualHost from the transport.
  <p>
  The DynamicVirtualHost & DynamicVirtualHostManager support/encapsulate
  delayed definition and activation of virtual hosts.