diff -r e853e5b5bfdf -r 5af9c7693d70 java/alt2xml-lib-input/src/cz/frantovo/alt2xml/ParserFactory.java
--- a/java/alt2xml-lib-input/src/cz/frantovo/alt2xml/ParserFactory.java	Sat Jun 07 22:12:11 2014 +0200
+++ b/java/alt2xml-lib-input/src/cz/frantovo/alt2xml/ParserFactory.java	Sat Jun 07 23:17:59 2014 +0200
@@ -20,6 +20,7 @@
 import java.util.Deque;
 import java.util.LinkedList;
 import java.util.ServiceLoader;
+import javax.xml.parsers.FactoryConfigurationError;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;
@@ -36,6 +37,16 @@
 public class ParserFactory extends SAXParserFactory implements ReaderFinder {
 
 	private final Deque<Alt2XmlReaderFactory> readerFactories = new LinkedList();
+	/**
+	 * @see #DEFAULT_FACTORY_PROPERTY
+	 */
+	private SAXParserFactory fallbackFactory;
+
+	/**
+	 * System property which contains SAXParserFactory class name for XML.
+	 * Will be used as fallback if no alternative factory matches systemId to be parsed.
+	 */
+	public static final String DEFAULT_FACTORY_PROPERTY = "cz.frantovo.alt2xml.fallback.javax.xml.parsers.SAXParserFactory";
 
 	public ParserFactory() {
 		super();
@@ -43,6 +54,51 @@
 			readerFactories.add(f);
 		}
 
+		readerFactories.add(new FallbackReaderFactory());
+	}
+
+	/**
+	 * @return factory to be used for XML documents (default/fallback)
+	 * @throws FactoryConfigurationError if fallback factory is the same one as this – avoid
+	 * infinite recursion.
+	 */
+	public SAXParserFactory getFallbackFactory() {
+		if (fallbackFactory == null) {
+			String className = System.getProperty(DEFAULT_FACTORY_PROPERTY);
+			if (className == null) {
+				fallbackFactory = SAXParserFactory.newInstance();
+			} else {
+				fallbackFactory = SAXParserFactory.newInstance(className, null);
+			}
+		}
+
+		if (fallbackFactory.getClass().equals(getClass())) {
+			throw new FactoryConfigurationError("Fallback factory is the same class as this one – avoid infinite recursion: " + getClass());
+		} else {
+			return fallbackFactory;
+		}
+	}
+
+	public void setFallbackFactory(SAXParserFactory fallbackFactory) {
+		this.fallbackFactory = fallbackFactory;
+	}
+
+	private class FallbackReaderFactory implements Alt2XmlReaderFactory {
+
+		@Override
+		public boolean canRead(String systemId) {
+			return true;
+		}
+
+		@Override
+		public XMLReader getReader() throws SAXException {
+
+			try {
+				return getFallbackFactory().newSAXParser().getXMLReader();
+			} catch (ParserConfigurationException e) {
+				throw new SAXException("Unable to instantiate the fallback factory.", e);
+			}
+		}
 	}
 
 	@Override
@@ -60,6 +116,9 @@
 		return new AltSAXParser(new SuperReader(this));
 	}
 
+	/**
+	 * TODO: feature for disabling default SAXParserFactory
+	 */
 	@Override
 	public void setFeature(String name, boolean value) throws ParserConfigurationException, SAXNotRecognizedException, SAXNotSupportedException {
 		throw new SAXNotSupportedException("Zatím není podporováno.");