private static Set<MediaType> mediaTypesListFromDomElement(Element node, String tag)
            throws TikaException {
        Set<MediaType> types = null;
        NodeList children = node.getChildNodes();
        for (int i = 0; i < children.getLength(); i++) {
            Node cNode = children.item(i);
            if (cNode instanceof Element) {
                Element cElement = (Element) cNode;
                if (tag.equals(cElement.getTagName())) {
                    String mime = getText(cElement);
                    MediaType type = MediaType.parse(mime);
                    if (type != null) {
                        if (types == null) {
                            types = new HashSet<>();
                        }
                        types.add(type);
                    } else {
                        throw new TikaException("Invalid media type name: " + mime);
                    }
                }
            }
        }
        if (types != null) {
            return types;
        }
        return Collections.emptySet();
    }
Provides a default configuration (TikaConfig).  Currently creates a
new instance each time it's called; we may be able to have it
return a shared instance once it is completely immutable.

@return default configuration
tika-core/src/main/java/org/apache/tika/config/TikaConfig.java