Java List to Map

 Set<String> oids = attendanceListResponseBodyDTOS.stream().map(o -> o.getOid()).collect(Collectors.toSet());

List<AttendanceDTO> resultDB = attendanceService.convertForRead(

attendanceService.getRepository().findByOidInAndIsDeleted(oids,Api.NO)

);

Map<String, AttendanceDTO> attendanceDTOMap = resultDB.stream().collect(

Collectors.toMap(AttendanceDTO::getOid, att -> att)

);