Answer by Alexei for API method to validate Facebook OAuth token

I am mainly a C# .NET developer, but Java code seems quite clear for me. Your code seems fine, but it might be slightly improved:

1. Here:

    catch (Exception e) {    response.setData("Exception occurred");    return response;}

   You might be interested in logging exception's details somewhere.

2. Reduce nesting (less "spaghetti", more readable). E.g.:

   if (authToken == null) {    response.setData("Token invalid, please log in");    return response;} else {

   else can be removed, as return will skip all the rest of the code

   Thus, the code might look like this:

   @ApiMethod(name = "getUserData", path = "get_user_data")public Bean getUserData(@Named("token") String token) {   Bean response = new Bean();   FacebookAuthToken authToken;   User user;   String userPersonalisedWelcome;   try {       authToken = ServerFacebookHelper.getAuthToken(token);   } catch (Exception e) {       response.setData("Exception occurred");       return response;   }   if (authToken == null) {      response.setData("Token invalid, please log in");      return response;   }   user = getUserFromDatabase(authToken);   if (user == null)       // what happens if something fails here?      user = registerUserInDatabase(authToken);   response.setData(user.getPersonalisedWelcome);   return response;}