public Map<String, Double> getAvgSallaryInEachDepartment()
	{
		Map<String, Double> avgSallaryInDepartments = new HashMap<>();
		
		Query avgSallaryPerDeptQuery = manager.createQuery("SELECT dep.departmentName, AVG(emp.sallary) FROM Department dep JOIN dep.employees emp GROUP BY dep");
		List results = avgSallaryPerDeptQuery.getResultList();
		
		for (Object result : results)
		{
			Object[] resultSet = (Object[])result;
			
			avgSallaryInDepartments.put((String)resultSet[0], (Double)resultSet[1]);
		}
		
		return avgSallaryInDepartments;
	}