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Java Read Facebook Wall

I'm building a web portal by using Java; besides other requirements, I'm struggling my mind one one very simple (at least at first view) requirement:
my customer wants on his portal the first N posts of his facebook wall
and he wants to read the first N tweets of his twitter page
Since my java code is based on Spring, I wanted to use spring social, spring social twitter and spring social facebook in order to satisfy the requirement
With twitter I had no problem; in fact I
created an app on twitter
got twitter app id and app secret
prepared code
In a couple of hours, all worked pretty good
Problems were born with facebook and it's a lot of time I'm fighting with it
I passed from spring social to facebook4j (since this last one seems to me stronger).
I did the following
created an app on FB
got the facebook appId and appSecret
told to the code that I need the read_stream permission
prepared the code
But I'm not able in reading posts from my wall
Is there anyone who was able in satisfying this kind of scenario?
here my facebook4j code
private static final Logger log = LoggerFactory.getLogger(FacebookTest.class.getName());
public static void main (String[] a)
{
try
{
ConfigurationBuilder cfgBui = new ConfigurationBuilder();
cfgBui.setDebugEnabled(true);
cfgBui.setOAuthAppId(myAppId);
cfgBui.setOAuthAppSecret(myAppSecret);
cfgBui.setUseSSL(true);
Configuration cfg = cfgBui.build();
FacebookFactory ff = new FacebookFactory(cfg);
OAuthSupport support = new OAuthAuthorization(cfg);
support.setOAuthPermissions("read_stream");
AccessToken appAccessToken = support.getOAuthAppAccessToken();
Facebook face = ff.getInstance(appAccessToken );
ResponseList<Post> posts = face.searchPosts("test");
for (Post post : posts)
{
System.out.println(post.getId());
}
} catch (Exception e)
{
log.error("Errore", e);
}
}
As far as I understood, I should need the user access token, but I don't know how to generate it; should I create a login flow and show to the user the FB login dialog? If so, why should I create app id and app secret? They have no sense in my scenario
Moreover...in my case...the server side should authenticate on FB and read posts from a well know user wall (the wall of my customer...) so....where should I present the login dialog? where should I redirect after the FB login?
Is there any good man :) who can clarify to me the FB read post flow?

You MUST use one of the possibilities to authorize the user (with read_stream) in order to get access to his stream. Here´s the link to all the possibilities: https://developers.facebook.com/docs/facebook-login/v2.2
You can also generate Access Tokens with the Graph API Explorer: https://developers.facebook.com/tools/explorer/
Detailed information about Access Tokens and how to generate them can be found in the following links:
https://developers.facebook.com/docs/facebook-login/access-tokens
http://www.devils-heaven.com/facebook-access-tokens/
Keep in mind that an Extended User Token only lasts for 60 days, after that your customer would have to refresh it manually. In general, you are not allowed to use User Profiles for commercial reasons, and it´s very unusual to show a User stream on a website.
Better: Use a Facebook Page. /page-id/feed with an Extended Page Token that lasts forever.

If you use spring-social-facebook, you could let the user login via (front-end login flow) and then you can access the users wall. However, user would need to login and authorize your app to perform the operations.
Here is a spring social sample project that demo's how spring-social-facebook login is done https://github.com/spring-projects/spring-social-samples
Also, within your java code you can use feedoperations to gather information about home feed and also query against it. Checkout the documentation.
facebook.feedOperations().

How to use the twitter4j library?

I was overwhelmed by the amount of information on https://dev.twitter.com/docs and then I went to twitter4j and downloaded the library. I got a consumer key and secret by registering on their website. What are these for?
What I am trying to is get tweet text from certain twitter account( not my personal one but public one) and other information( account user, time and other stuff).
I couldn't find useful tutorial online. So please help me. Thank you very much!

The keys are so that your application can authenticate to the Twitter API. I put them in a properties file and made them available on the classpath. Once your application has authenticated, you will be able to use the API to get the account information you need. I don't know any good tutorials, but you could use an open source project I wrote as a reference if you like: https://github.com/rossh/gift-findr.

This is an example of how to get hold of a org.twitter4j.Twitter object. Once you have that, you can do a great many operations - just inspect the interface for org.twitter4j.Twitter.
Twitter twitter = new TwitterFactory().getInstance(twitter4JConfiguration);
twitter.setOAuthConsumer(consumerKey, consumerSecret);
twitter.setOAuthAccessToken(new AccessToken(oauthToken, oauthTokenSecret));
String screenName = twitter.getScreenName(); // Returns authenticating user's screen name.
User stephenfry = twitter.showUser("stephenfry"); // Returns extended information of a given user ...
List<User> friends = twitter.getFriendsList("stephenfry", -1L); // Returns a cursored collection of user objects ...
This is a link to the javadoc for the org.twitter4j.Twitter interface

Send multiple tweets(mentions) with multiple accounts Twitter4j

I am designing an application using which the users would be able to send multiple tweets(mentions) from multiple accounts and am using Twitter4j for the same. Regarding this, I have a few questions:
Authentication: The application has an authentication part.I am able to authenticate using the PIN based authentication(oob).But I want to know if it is possible to persist the access token such that the user only needs to authenticate once at the time of installing the app and never thereafter.
Exception Handling: The application would be sending multiple tweets.So I wish to know that what would be the way to check for exceptions, particularly the suspension of user account.
Limit: What would be a safe rate(I mean minimum interval between two tweets) to send the tweets hourly or per minute. Does twitter also check for the IP of the machine for suspending the accounts? I mean suppose I need to send 60 tweets.If I am using 4 accounts to do the same with 15 tweets per account and run 4 threads for the same, will that allow me to send more tweets form my app?
EDIT
Kindly note that I am making a desktop app, not a web app.So a PIN based authentication is necessary. Also I am not sure about the validity lifetime of an access token.Will the access token once generated by using OOB authentication be valid forever so that I can save it in a database and hence enable user to authenticate only once?

Some points to note:
Authentication : It is possible to get the access token without using pin based authentication, for that when you create an application you have to specify a callback url, and so you dont have to copy and paste the pin, instead a parameter oauth_verifier is appended with the callback url which you can fetch from the url itself. With this oauth_verifier , you can get access_token and token_secret as mentioned here
Exception Handling : Nothing other than simple try catch can be more helpful here.
Limit: There are two initial buckets available for GET requests: 15 calls every 15 minutes, and 180 calls every 15 minutes. Refer here for more details.
Edit: For desktop app there is no other alternative, so you have to do a pin based authentication and since twitter works on Oauth1, so as of now, the validity of the access_token and token_secret is lifetime. So authentication is required only once and the api calls can be made using same tokens.

Scribe - multiple callback simultaneously

I am making a module for a server software that is allowing support for facebook.
The problem is with the callback URL. If one client start the authorization proccess, then another client starts the proccess at the same time, or before the first user finish. How could I check what user finished first?
I need a way to check what client's callback I'm getting. One solution would be to lock other from register until the first one has finished, but I don't want to do that. Is there another way? I have thought about including ?client=clientid at the end of the callback, but I heard facebook only allows the exact url specified in the app on facebook.
UPDATE
It didn't work to add client="clientid" to the callback. Any other ideas?

After some more searchig I figured facebook will allow a parameter: state. (thanks to #jacob https://stackoverflow.com/a/6470835/1104307)
So I just did ?state=clientId.
For anyone using scribe the code is this:
service.getAuthorizationUrl(null) + "&state=" + clientId;

I think there is no problem on adding and GET parameter like client=clientID. Facebook will redirect you to the URL you have specified and using the REQUEST parameters you can check who completed the request. The problem exist if you have specified URL as http://yoursite.com and pass redirect to http://some-sub-domain.yoursite.com or entirely different location.

if you are using the server-side flow then the oauth 2 flow will be:
redirect user to facebook
facebook then rediects the user to your specified callback
your server uses something like curl to get the access token
your server does some more curl to get maybe more user data or update the user's data
my recommendation would be to set a session cookie in step 1 and simultaneously store this session id on your server. then the session cookie will automatically be sent to the callback url in step 2 and you can identify the session in the database this way.
this will work for all service providers (google, twitter, linkedin, etc) and is the preferred way of maintaining session continuity.

TwitterException {statusCode=403, retryAfter=0, rateLimitStatus=null}

I have recently noticed that I keep getting a 403 error while doing twitter search. My application was working until couple of days back when i noticed the error.
I checked with Twitter & they say my IP is not blocked, I am also within the rate limit = about 60 search requests/per hour.
Here's how i was initializing the Twitter object -
private static Twitter TWITTER_CLIENT = new TwitterFactory().getInstance();
After i noticed the error, i tried the following & still no success -
private static Twitter TWITTER_CLIENT = new TwitterFactory().getInstance("user", "password");
Here's how i am searching -
TWITTER_CLIENT.search(new Query("#keyword1 OR #keyword2"));
I tried this URL (curl http://search.twitter.com/search.json?q=ipad) from my server & it works alright.
Following is the exception. I am on java6 + Twitter4j v2.1.2. Would really appreciate any help. Thanks.
TwitterException{statusCode=403, retryAfter=0, rateLimitStatus=null}
at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:301)
at twitter4j.internal.http.HttpClientWrapper.request(HttpClientWrapper.java:68)
at twitter4j.internal.http.HttpClientWrapper.get(HttpClientWrapper.java:82)
at twitter4j.Twitter.search(Twitter.java:193)

Most likely the reason is basic auth shutdown by Twitter (aka OAuthcalypse):
Basic Auth Shutdown
You need to switch to using OAuth.

Recently i got the same error while executing similar code.
To fix it, please go to
https://apps.twitter.com/app/your_app_id
Click on Keys and access token
In Access Level, click modify app permission and choose the 3rd option: Read, Write and Access direct messages
Click on update. ( Note: you might have to add your mobile no and verify with otp to get this access if you dont have your no added in twitter)
Regenerate both Consumer key & secretand Access token & secret using the clickable button
Us e the new keys in your program
And you are done! Your program will start working.