code: @SuppressWarnings("unchecked")
      public Set<String> getServiceHandlerNames() {
          Map<String, Object> serviceHandlers = getServiceHandlers(false);
          if (serviceHandlers == null) {
              return Collections.EMPTY_SET;
          }
          return serviceHandlers.keySet();
      }
docs: Return set of service handler names. Removing entries from the set unregisters the corresponding service handler.
  
  @return Set of service handler names