code: public synchronized void storeToXML(OutputStream os, String comment,
                                         String encoding)
          throws IOException
      {
          if (os == null)
              throw new NullPointerException();
          XMLUtils.save(this, os, comment, encoding);
      }
docs: Emits an XML document representing all of the properties contained
  in this table, using the specified encoding.
  
  <p>The XML document will have the following DOCTYPE declaration:
  <pre>
  &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"&gt;
  </pre>
  
  <p>If the specified comment is <code>null</code> then no comment
  will be stored in the document.
  
  <p>The specified stream remains open after this method returns.
  
  @param os the output stream on which to emit the XML document.
  @param comment a description of the property list, or <code>null</code>
  if no comment is desired.
  @throws IOException if writing to the specified output stream
  results in an <tt>IOException</tt>.
  @throws NullPointerException if <code>os</code> is <code>null</code>,
  or if <code>encoding</code> is <code>null</code>.
  @throws ClassCastException  if this <code>Properties</code> object
  contains any keys or values that are not
  <code>Strings</code>.
  @see    #loadFromXML(InputStream)
  @since 1.5