- I have the following data… in the form of Years and Months in my resultSet and I want to remove redundant years and months to create xml elements as: - [2015, 2016, 2017] [05, 06, 07, 08, 09, 10, 11, 12, 01, 02, 03, 04] 
and I am trying to generate XML Tags out of this data Year and Month wise as:
<Root>
<Year Y="2015">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
<Year Y="2016">
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
<Year Y="2017">
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
</Root>
But the output I am getting is as:
<Root>
<Year Y="2015">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/> 
<Month M="03"/>
<Month M="04"/>
</Year>
<Year Y="2016">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
</Year>
<Year Y="2017">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
</Year>
</Root>
That is how I am tackling my problem
try{
            //Connection
        connection = DriverManager.getConnection(conUrl);
        statement = connection.createStatement();
        resultSet = statement.executeQuery(query);
            //XML 
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        Document document = documentBuilder.newDocument();
            // Super Root Node (Necessity)
        Element necessaryElement = document.createElement("Root");
        document.appendChild(necessaryElement);
        while(resultSet.next()){
            //Year Array populating
            monitoringYear  = resultSet.getString("Year");
            monitoringYearArray.add(monitoringYear);
            //Month Array populating
            monitoringMonth = resultSet.getString("Month");
            System.out.println( "Monitoring Month "+ monitoringMonth);
            monitoringMonthArray.add(monitoringMonth);
        }
                    // remove duplicate from the Years ArrayList and retain the order
                Set<String> uniqueYearList = new LinkedHashSet<String>(monitoringYearArray);
                monitoringYearArray.clear();
                monitoringYearArray.addAll(uniqueYearList); 
                // Remove duplicate from the Month ArrayList and retain the order
                Set<String> uniqueMonthList = new LinkedHashSet<String>(monitoringMonthArray);
                monitoringMonthArray.clear();
                monitoringMonthArray.addAll(uniqueMonthList);
                    // XML Element for the Year
                for(int year = 0; year < monitoringYearArray.size(); year++){
                        // Super Root Node (Year)
                    Element yearElement = document.createElement("Year");
                    necessaryElement.appendChild(yearElement);
                    Attr yearAttr = document.createAttribute("Y");
                    yearAttr.setValue(monitoringYearArray.get(year));
                    yearElement.setAttributeNode(yearAttr);
                            // XML Element for the Month
                        for(int month = 0; month < monitoringMonthArray.size(); month++){
                                // Sub Root Node (Month)
                            Element monthElement = document.createElement("Month");
                            yearElement.appendChild(monthElement);
                            Attr monthAttr = document.createAttribute("M");
                            monthAttr.setValue(monitoringMonthArray.get(month));
                            monthElement.setAttributeNode(monthAttr);
                        }
                }
If you have any suggestions how to solve the problem, i would greatly appreciate Thanks
 
    