ax.xml.transform.OutputKeys} class. Other strings can be
specified as well.
If the transformer does not recognize an output key, a
{@link java.lang.IllegalArgumentException} is thrown, unless the
key name is <a href="#qname-delimiter">namespace qualified</a>. Output key names
that are namespace qualified are always allowed, although they may be
ignored by some implementations.</p>

<p>If all that is desired is the simple identity transformation of a
source to a result, then {@link javax.xml.transform.Transf