How can I get a Twitter public timeline with no user authentication using Twitter4j?

I've wrote some code to allow a user to login to his Twitter account and send Tweet using Twitter4j and following this tutorial.

Now I can also get the tweets of a public account using

ConfigurationBuilder cb = new ConfigurationBuilder();
cb.setHttpConnectionTimeout(10000)
.setHttpReadTimeout(10000)
.setOAuthConsumerKey(Config.TWITTER_CONSUMER_KEY)
.setOAuthConsumerSecret(Config.TWITTER_CONSUMER_SECRET)
.setOAuthAccessToken(Utils.getPrefsString(getActivity(),
    TwitterPrefsFragment.PREF_KEY_OAUTH_TOKEN, "")) // empty if not authentified
.setOAuthAccessTokenSecret(Utils.getPrefsString(getActivity(),
    TwitterPrefsFragment.PREF_KEY_OAUTH_SECRET, "")); // empty if not authentified
TwitterFactory tf = new TwitterFactory(cb.build());
Twitter twitter = tf.getInstance();

List<twitter4j.Status> statuses = twitter.getUserTimeline(SOME_PUBLIC_TWITTER_ACCOUNT, new Paging(1, 50));

but this only works when the user is authenticated and the app has the oauth token and secret in the preferences..

How can I get a Twitter public timeline with no Access Token, i.e. without having the user to authenticate?

EDIT

I'm reformulating my question to make it clearer:

I managed to authenticate my Twitter app and a user with the code given here.

Now, if the user is not logged in, how can I get a public timeline? In that case, there is no OAUTH_TOKEN and OAUTH_SECRET, and the request shown above does not work because an empty string is set to ConfigurationBuilder.setOAuthAccessToken and ConfigurationBuilder.setOAuthAccessTokenSecret.

So what is, if it exists, the request to get a public timeline, with no OAUTH_TOKEN and OAUTH_SECRET?

Solution

This is certainly possible and I have already tried it. If your doubt is only regarding the Access Token and Access Token secret being empty, then you should try to use the Access Token provided in the app page. By app page I mean, the link where you have registered your twitter app.

If you go to dev.twitter.com ,and go to your app settings, you can see a consumer key, consumer secret, access token and access token secret. Make use of these and follow my below code and it should work,

ConfigurationBuilder cb = new ConfigurationBuilder();
        cb.setDebugEnabled(true)
                .setOAuthConsumerKey("B*************Q")
                .setOAuthConsumerSecret(
                        "l*************o")
                .setOAuthAccessToken(
                        "1*************s")
                .setOAuthAccessTokenSecret(
                        "s*************s");
        TwitterFactory tf = new TwitterFactory(cb.build());
        twitter = tf.getInstance();
        try {
            List<Status> statuses;
            String user;
            user = "Replace this with the screen name whose feeds you want to fetch";
            statuses = twitter.getUserTimeline(user);
            Log.i("Status Count", statuses.size() + " Feeds");

        } catch (TwitterException te) {
            te.printStackTrace();
        }

I used twitter 4j 3.03.jar for this.