code: public void setPreferredClientType(ClientType preferredClientType) {
      if (null == preferredClientType) {
        this.preferredClientType = ClientType.CLI;
      } else {
        this.preferredClientType = preferredClientType;
      }
    }
docs: Sets the preferred client type.
  
  @param preferredClientType
  The type to set as the preferred client type. If the value is null, then the preferred
  client type is set to <code>ClientType.CLI</code>.