Change property attribute object of an final object

Question

Argument of an method is final object. Why?

Does it means that in this method (service) this object (response) is like final class (You cannot override methods of that class /HttpServletResponse/ in this object /response/)?

Or it means that in this scope (inside this method /service/) You can't change reference of that argument object (response) to another, let say new, HttpServletResponse instance (in that scope)?

Like:

response = new HttpServletResponse();

Here is a code example:

public class ServletLifeCycleExample extends HttpServlet {

    private int count;
...
    @Override
    protected void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException {
        getServletContext().log("service() called");
        count++;
        response.getWriter().write("Incrementing the count to " + count);
    }
...
}

Your question is not clear. Do you mean why final method argument is used? — Shafin Mahmud, Jul 24 '18 at 10:16
See this if it satisfies your quest. https://stackoverflow.com/questions/4162531/making-java-method-arguments-as-final — Shafin Mahmud, Jul 24 '18 at 10:18
its not me bro :| I just tried to clearify your asking, I find no reason to give a -1. You have certain point of your query. — Shafin Mahmud, Jul 26 '18 at 15:31

Shanu Gupta · Answer 1 · 2018-07-24T10:26:09.127

2

Like you said final indicates that you can't change the reference to something else.

i.e.

response = new HttpServletResponse();

or

response = null;

are prohibited.

But you can change the attributes of response object

i.e. something like

response.setStatus(status)

would be allowed.

edited Jul 24 '18 at 10:26

answered Jul 24 '18 at 10:19

Shanu Gupta

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As I thought, just...Didn't think about null. Why I can't change it to null? (Add that to answer pls) – zelenooq Jul 24 '18 at 10:47
@zelenooq assigning to `null` would come under changing reference and we can't do that to `final` variables. – Shanu Gupta Jul 24 '18 at 10:52

Change property attribute object of an final object

1 Answers1