Program: 4298
Project: 4298
Buggy source:
private List<Integer> generateDayCandidatesQuestionMarkSupported(int year,int month,WeekDay mondayDoWValue){
  DateTime date=new DateTime(year,month,1,1,1);
  Set<Integer> candidates=Sets.newHashSet();
  if (daysOfMonthCronField.getExpression() instanceof Always || daysOfWeekCronField.getExpression() instanceof Always) {
    candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
  }
 else {
    if (daysOfMonthCronField.getExpression() instanceof QuestionMark) {
      candidates.addAll(FieldValueGeneratorFactory.createDayOfWeekValueGeneratorInstance(daysOfWeekCronField,year,month,mondayDoWValue).generateCandidates(-1,date.dayOfMonth().getMaximumValue()));
    }
 else {
      if (daysOfWeekCronField.getExpression() instanceof QuestionMark) {
        candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
      }
 else {
        candidates.addAll(FieldValueGeneratorFactory.createDayOfWeekValueGeneratorInstance(daysOfWeekCronField,year,month,mondayDoWValue).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
        candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
      }
    }
  }
  List<Integer> candidatesList=Lists.newArrayList(candidates);
  Collections.sort(candidatesList);
  return candidatesList;
}

Fixed version (ground truth):
private List<Integer> generateDayCandidatesQuestionMarkSupported(int year,int month,WeekDay mondayDoWValue){
  DateTime date=new DateTime(year,month,1,1,1);
  Set<Integer> candidates=Sets.newHashSet();
  if (daysOfMonthCronField.getExpression() instanceof Always && daysOfWeekCronField.getExpression() instanceof Always) {
    candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
  }
 else {
    if (daysOfMonthCronField.getExpression() instanceof QuestionMark) {
      candidates.addAll(FieldValueGeneratorFactory.createDayOfWeekValueGeneratorInstance(daysOfWeekCronField,year,month,mondayDoWValue).generateCandidates(-1,date.dayOfMonth().getMaximumValue()));
    }
 else {
      if (daysOfWeekCronField.getExpression() instanceof QuestionMark) {
        candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
      }
 else {
        candidates.addAll(FieldValueGeneratorFactory.createDayOfWeekValueGeneratorInstance(daysOfWeekCronField,year,month,mondayDoWValue).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
        candidates.addAll(FieldValueGeneratorFactory.createDayOfMonthValueGeneratorInstance(daysOfMonthCronField,year,month).generateCandidates(1,date.dayOfMonth().getMaximumValue()));
      }
    }
  }
  List<Integer> candidatesList=Lists.newArrayList(candidates);
  Collections.sort(candidatesList);
  return candidatesList;
}