String inputXML = "<table > <tbody> <ul> <li>Li1</li> <li>Li2</li> <li>Li3</li></ul></tbody></table>";
XMLSerializer xmlSerializer = new XMLSerializer();
JSON json = xmlSerializer.read( inputXML );
System.out.println("json = "+json.toString(2));

->
json = [[[
  "Li1",
  "Li2",
  "Li3"
]]]