code: public synchronized void storeToXML(OutputStream os, String comment)
          throws IOException
      {
          if (os == null)
              throw new NullPointerException();
          storeToXML(os, comment, "UTF-8");
      }
docs: Emits an XML document representing all of the properties contained
  in this table.
  
  <p> An invocation of this method of the form <tt>props.storeToXML(os,
  comment)</tt> behaves in exactly the same way as the invocation
  <tt>props.storeToXML(os, comment, "UTF-8");</tt>.
  
  @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 null.
  @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