Would expect to be able to render a single column table. Following code does not render a table.
final String input = "| First Header |\n" +
"| ------------- |\n" +
"| Content Cell |\n" +
"| Content Cell |\n";
List<Extension> extensions = Arrays.asList(TablesExtension.create());
Parser parser = Parser.builder().extensions(extensions).build();
Node document = parser.parse(input);
HtmlRenderer renderer = HtmlRenderer.builder().extensions(extensions).build();
System.out.println(renderer.render(document));