Xpath

import java.io.File;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;

public class Test {

    public static void main(String[] args) {
        parseXML();
    }
    private static void parseXML() {
        try {
            XPathFactory xpathFactory = XPathFactory.newInstance();
            XPath xpath = xpathFactory.newXPath();
            
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse(new File("one.xml"));
            
            XPathExpression xpathExpression = xpath.compile("//users/user[@age > 11]/id");
            String id = (String)xpathExpression.evaluate(doc, XPathConstants.STRING);
            System.out.println(id);
            
        } catch(Exception e) {
            e.printStackTrace();
        }
    }
}

 one.xml:

<?xml version="1.0" encoding="UTF-8"?>
<users>
    <user school="A" age="10">
        <id>1001</id>
        <name>abc</name>
    </user>
    <user school="B" age="11">
        <id>1002</id>
        <name>efg</name>
    </user>
    <user school="C" age="12">
        <id>1003</id>
        <name>hij</name>
    </user>
</users>