When parsing a large size xml file , OutOfMemorry exception(attach code)

Question

Dear all ,
I met a OutOfMemorry exception when I parse a xml file (20M) in my application(I extract data in xml file for building my application data), but I found that it take long time(for 2 more minutes) even just searching the xml file , because my application is viewed by web page , so it's too bad for waiting.
what I used is org.jdom.input.SAXBuilder(jdom1.0beta8-dev) , and my xml file structure is like :
<errors>
<item1>content</item1>
<item2>content</item2>
</errors>
and this is my source code of parsing xml file :
import java.io.*;
import java.text.*;
import java.util.*;
import org.jdom.*;
import org.jdom.input.*;
import org.jdom.output.*;
public class XMLProperties {
    private File file;
    private Document doc;
    private Map propertyCache = new HashMap();
    public XMLProperties(String filename) {
            SAXBuilder builder = new SAXBuilder();
            // Strip formatting
            DataUnformatFilter format = new DataUnformatFilter();
            builder.setXMLFilter(format);
            long time_start = System.currentTimeMillis();
            Runtime run = Runtime.getRuntime();
            doc = builder.build(new File(filename));
            System.out.println("Build doc memory ="+(run.totalMemory()-
                     run.freeMemory())/1024+"K");
            System.out.println("Build doc used time :"+(
                     System.currentTimeMillis()-time_start)/1000+" s");
        catch (Exception e) {
            System.err.println("Error creating XML parser in "
                + "PropertyManager.java");
            e.printStackTrace();
     public String [] getChildrenProperties(String parent) {
        // Search for this property by traversing down the XML heirarchy.
        Element element = doc.getRootElement();
        element = element.getChild(parent);
        if (element == null) {
            // This node doesn't match this part of the property name which
            // indicates this property doesn't exist so return empty array.
            return new String [] { };
        // We found matching property, return names of children.
        List children = element.getChildren();
        int childCount = children.size();
        String [] childrenNames = new String[childCount];
        for (int i=0; i<childCount; i++) {
            childrenNames[i] = ((Element)children.get(i)).getName();
        return childrenNames;
    }the test main class:
import java.util.Map;
import java.util.HashMap;
import org.jdom.*;
import org.jdom.input.*;
public class MyTest {
  public static void main(String[] args) {
    long time_start = System.currentTimeMillis();
    Runtime run = Runtime.getRuntime();
    Map childs = new HashMap();
    System.out.println("Used memory before="+(run.totalMemory()-run.freeMemory())/1024 + "K");
    XMLProperties parser = new XMLProperties("D:\\projects\\edr\\jsp\\status-data\\edr-status-2003-09-01.xml");
    String[] child = parser.getChildrenProperties("errors");
    for(int i=0;i<child.length;i++) {
//      childs.put(new Integer(i), child);
if(i%1000 == 0) {
System.out.println("Used memory while="+(run.totalMemory()-run.freeMemory()/1024+"K"));
System.out.println("child.length="+child.length);
System.out.println("Used memory after="+(run.totalMemory()-run.freeMemory())/1024+"K");
System.out.println("Time used: "+(System.currentTimeMillis()-time_start)/1000+"s");
The result is : Used memory before=139K
Used memory while=56963K
Used memory after=51442K
child.length=27343
Time used: 146s
is that some way to solve this problem ?
Thanks for your help

Answer 1

I met a OutOfMemorry exception when I parse a xml
l file (20M) in my application(I extract data in xml
file for building my application data)...Rule of thumb for parsing XML: the memory you need is about 10 times the size of the XML file. So in your case you need 200 MB of free memory.
, but I found
that it take long time(for 2 more minutes) even just
searching the xml file , because my application is
viewed by web page...Then you need to redesign your application. Parsing 20 megabytes of XML for every request is -- as you can see -- impractical. Sorry I can't suggest how, since I have no idea what your application is.