Map<String, Person> employeesMap = (Map<String, Person>) system.query(new GetEmployee());
List<Person> employees = new ArrayList<Person>();
employees.addAll(employeesMap.values());
SortComparator comparator = new SortComparator();
Collections.sort(employees, comparator);
for (Person employee : employees) {
TableItem item = new TableItem(employeeTable, SWT.NONE);
String dismissedDateText = ((Employee) employee.getPersonType("employee")).getDismissedDate();