invoke servlet and transform json string into object

InvokeServlet.js

// servlet is local to the app
String requestURL = request.getRequestURL().toString();
String servletPath = request.getServletPath();
String serverPath = requestURL.substring(0,requestURL.indexOf(servletPath));
URL url = new URL(serverPath + "/getScores");
		   
URLConnection conn = url.openConnection();
conn.setConnectTimeout(12000);
InputStream is = conn.getInputStream();
        
StringWriter writer = new StringWriter();
IOUtils.copy(is, writer, "UTF-8");
        
String jsonStr = writer.toString();
			
Gson gson = new Gson();
Type listType = new TypeToken<List<ScoreRecord>>() {}.getType();
List<ScoreRecord> scores = gson.fromJson(jsonStr, listType);