how to initialize class object as null in java

1protected void doPost(HttpServletRequest request, HttpServletResponse response) 
2  throws ServletException, IOException {
3    // Note that unless except in certain cases (IoC)
4    // this scenario is quite easy to avoid
5    Object_DTO object_DTO = null;
6
7    if(request.getParameter("parameter").equals("hello")) {
8        object_DTO = new Object_DTO(); // here null object initialized to a new object
9        object_DTO.setAttr("attr");
10        ...
11    } else if (request.getParameter("parameter").equals("goodbye")) {
12        object_DTO = new Object_DTO();
13    }
14
15    if (object_DTO == null) {
16        // Bad response
17    }
18}
19