TransformerHandler throws OutOfMemoryError with large xml files

Question

i'm using TransformerHandler to convert any content to SAX events and transform it using XSLT into an XML file.
the problem is that for large amount of content i get a OutOfMemoryError.
it seams that the content is kept in memory and only flushed when i call handler.endDocument();
i tried using auto flush writers as the Result, or call the flush() method myself, but nothing.
here is the example - pls help!
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.xml.sax.helpers.AttributesImpl;
public class Test
      * test handler memory usage
      * @param loops no of loops - when large enogh - OutOfMemoryError !!!
      * @param xsltFilePath xslt file
      * @param targetXmlFile output xml file
      * @throws Exception
     public static void testHandlerMemUsage(int loops, String xsltFilePath, String targetXmlFile)throws Exception
          //verify SAX support
          TransformerFactory factory = TransformerFactory.newInstance();
          if(!factory.getFeature(SAXTransformerFactory.FEATURE))
               throw new UnsupportedOperationException("SAX tranformations not supported");
          TransformerHandler handler=
               ((SAXTransformerFactory)factory).newTransformerHandler(new StreamSource(xsltFilePath));
          handler.setResult(new StreamResult(targetXmlFile));
          handler.startDocument();
          handler.startElement(null,"root","root",new AttributesImpl());
          //loop
          for(int i=0;i<loops;i++)
               handler.startElement(null,"el-"+i,"el-"+i,new AttributesImpl());
               handler.characters("value".toCharArray(),0,"value".length());
               handler.endElement(null,"el-"+i,"el-"+i);
          handler.endElement(null,"root","root");
          //System.out.println("end document");
          //only after endDocument() starts to print..
          handler.endDocument();
          //System.out.println("ended document");
     public static void main(String[] args)throws Exception
          System.out.println("--starting..");
          testHandlerMemUsage(500000,"/copy.xslt","/testHandlerMemUsage.xml");
          System.out.println("--we are still here -- increase loops..");
}

Answer 1

Did you try increasing memeory when starting java with the -Xmx parameter? You know that java uses only 64MB by default, so you might need to increase it to e.g. 256MB for your XML to work.