code: public List<InstanceInfo> getInstancesBySecureVirtualHostName(String secureVirtualHostName) {
          return Optional.ofNullable(this.secureVirtualHostNameAppMap.get(secureVirtualHostName.toUpperCase(Locale.ROOT)))
                  .map(VipIndexSupport::getVipList)
                  .map(AtomicReference::get)
                  .orElseGet(Collections::emptyList);        
      }
docs: Gets the list of secure <em>instances</em> associated to a virtual host
  name.
  
  @param secureVirtualHostName
  the virtual hostname for which the secure instances need to be
  returned.
  @return list of <em>instances</em>.