persistentStudent.lockWrite(student); student.getExamsEnrolled().remove(exam);  IPersistentExamStudentRoom persistentExamStudentRoom = sp.getIPersistentExamStudentRoom(); ExamStudentRoom examStudentRoom = (ExamStudentRoom) persistentExamStudentRoom.readBy(exam, student);
IPersistentExamStudentRoom persistentExamStudentRoom = sp.getIPersistentExamStudentRoom(); ExamStudentRoom examStudentRoom = (ExamStudentRoom) persistentExamStudentRoom.readBy( exam, student);
	public Boolean run(String username, Integer examId) throws FenixServiceException {		try {			ISuportePersistente sp = SuportePersistenteOJB.getInstance();			IPersistentStudent persistentStudent = sp.getIPersistentStudent();			IStudent student = persistentStudent.readByUsername(username);			if (student != null) {				IPersistentExam persistentExam = sp.getIPersistentExam();				IExam exam = new Exam();				exam.setIdInternal(examId);				exam = (IExam) persistentExam.readByOId(exam, true);				persistentStudent.lockWrite(student);				student.getExamsEnrolled().remove(exam);				IPersistentExamStudentRoom persistentExamStudentRoom = sp.getIPersistentExamStudentRoom();				ExamStudentRoom examStudentRoom = (ExamStudentRoom) persistentExamStudentRoom.readBy(exam, student);				if (examStudentRoom != null) {					persistentExamStudentRoom.delete(examStudentRoom);				}			}		} catch (ExcepcaoPersistencia e) {			throw new FenixServiceException(e);		}		return new Boolean(true);	}