code: public void setUserInfo(int userId, String userName, int groupId, String groupName) {
          this.userId = userId;
          this.userName = userName;
          this.groupId = groupId;
          this.groupName = groupName;
      }
docs: Set user and group information that will be used to fill in the tar archive's entry headers. Since Java currently
  provides no means of determining a user name, user id, group name, or group id for a given File, TarArchive
  allows the programmer to specify values to be used in their place.
  
  @param userId
  The user Id to use in the headers.
  @param userName
  The user name to use in the headers.
  @param groupId
  The group id to use in the headers.
  @param groupName
  The group name to use in the headers.