returns the server error occurred . concode_field_sep UserChallengesDTO[] userChallengesDTOs concode_elem_sep String error concode_elem_sep String key concode_field_sep String getKey concode_elem_sep UserChallengesDTO[] getUserChallengesDTOs concode_elem_sep void setUserChallengesDTOs concode_elem_sep void setError concode_elem_sep void setKey
String function ( ) { return error ; }