Unable to parse XML tags within other tags using SAX Parser in Groovy

I have this sample xml format that I am trying to parse.

<records>
      <ae_documentTitleBegin /><ae_subDocumentTitleGenerated generatedTitle="Introduction" /><ae_750584b7e5364775bf21d91c5020b965_clauseBegin /><ae_clauseTitleBegin />Introduction<ae_clauseTitleEnd /><ae_clauseBodyBegin />ABL <ae_definedTermInstanceBegin />CREDIT AGREEMENT<ae_definedTermInstanceEnd /><ae_documentTitleEnd />
      <car name='HSV Maloo' make='Holden' year='2006'>
        <ae_definedTermTitleBegin />Australia<ae_definedTermTitleEnd />
        <ae_clauseTitleBegin />1.02 <u>Accounting Terms </u>.<ae_clauseTitleEnd />

      </car>
      <car name='P50' make='Peel' year='1962'>
        <ae_definedTermTitleBegin />Isle of Man<ae_definedTermTitleEnd />
        <ae_clauseTitleBegin />Smallest Street-Legal Car at 99cm wide and 59 kg in weight<ae_clauseTitleEnd />
      </car>
      <car name='Royale' make='Bugatti' year='1931'>
        <ae_definedTermTitleBegin />France<ae_definedTermTitleEnd />
        <ae_clauseTitleBegin />Most Valuable Car at $15 million<ae_clauseTitleEnd />
      </car>
    </records>

The sax parser that I have implemented looks like

import javax.xml.parsers.SAXParserFactory
import org.xml.sax.helpers.DefaultHandler
import org.xml.sax.*

class SAXXMLParser extends DefaultHandler {
    ArrayList<String> DefinedTermTitles = new ArrayList<>();
    ArrayList<String> ClauseTitles = new ArrayList<>();
    ArrayList<String> DocumentTitles = new ArrayList<>();
    String currentMessage;
    boolean countryFlag = false;
    StringBuilder message = new StringBuilder();

    void startElement(String ns, String localName, String qName, Attributes atts) {
        switch (qName) {
            case 'ae_clauseTitleBegin':
                //messages.add(currentMessage)
                countryFlag = true;
                break

            case 'ae_documentTitleBegin':
                //messages.add(currentMessage)
                countryFlag = true;
                break

            case 'ae_definedTermTitleBegin':
                //messages.add(currentMessage)
                countryFlag = true; 
                break           
         }      
    }   

    void characters(char[] chars, int offset, int length) {
        if (countryFlag) {
            message.append(new String(chars, offset, length));
            //println(currentMessage)
        }
    }

    void endElement(String ns, String localName, String qName) {
        switch (qName) {        
            case 'ae_clauseTitleEnd':
                ClauseTitles.add(message.toString());
                countryFlag = false;
                message.setLength(0);
                break
            case 'ae_documentTitleEnd':
                DocumentTitles.add(message.toString());
                countryFlag = false;
                message.setLength(0);
                break
            case 'ae_definedTermTitleEnd':
                DefinedTermTitles.add(message.toString());
                countryFlag = false; 
                message.setLength(0);
                break
         }
    }
}

The out put that I am getting is

Calling XML Parser
[Australia, Isle of Man, France] <<-- DefinedTermTitles

[Introduction, 1.02 Accounting Terms ., Smallest Street-Legal Car at 99cm wide and 59 kg in weight, Most Valuable Car at $15 million] <<-- ClauseTitles

[] <<-- DocuemntTitles
ENd of XML Parser

which is wrong. As you can see in the second list Introduction has come which should be in the third list of DocumentTitles(since I am appending document title tag to that list). Also Introduction is not correct It should be Introduction ABL CREDIT AGREEMENT. I have no idea why this is happening. I guess its because of having tags within tags. I need a way to get only the text ignoring the tags