Java: Jackson Data Binding Fails to Map Entire Class from JSON File

Question

I am trying to map a JSON file to a java class called Tweets.java, and I am able to bind and retrieve the data from the first part of the JSON file (the tweet class) but the Jackson ObjectMapper is failing to map the nested classes of Tweets.Java (the classes user and entities).

Here is the method where I am accessing the class that the JSON is being binded to:

WeatherDatabaseCreator.java

    //Read in files to be parsed.
    for (int i = 0; i < twitterFiles.size(); i++) {

        File twitterFile = twitterFiles.get(i);
        WeatherTweetParser wtp = new WeatherTweetParser(twitterFile);
        wtp.mapJavaObject();

        tws = new Tweets();
        tweets = tws.getTweets();

        System.out.print(tweets.size());

        tweetIndex = 0;

        System.out.println("Parsing and inserting twitter file '" + twitterFile.getAbsolutePath() + "'...");

    //Step through all the tweets in each file, using the TweetParser class.
    while (true) {
        tweet = tweets.get(tweetIndex);
        user = tweet.new User();
        entity = tweet.new Entities();

        userMentions = entity.getUserMentions();
        hashtags = entity.getHashtags();

        if (tweet.getText() == null) {
            break;
        }
        numParsed++;

        Boolean success = wdbm.insertTweet(tweet, user);
        if (success == true) {
            numInserted++;
        }

        if (entity.getNumHashtags() > 0){

            for (int j = 0; j < entity.getNumHashtags(); j++) {
                wdbm.insertHashtag(tweet, hashtags.get(j)); 
            }   
        }

        if (entity.getNumUserMentions() > 0) {

            for (int k = 0; k < entity.getNumUserMentions(); k++) {
                wdbm.insertReference(tweet, userMentions.get(k));
            }
        }

        if (numParsed % UPDATE_INTERVAL == 0) {
            System.out.println(numParsed + " tweets parsed. " + numInserted + " tweets inserted into database...");
        }

        tweetIndex++;
    }

Here is part of the JSON File. The file is made up of an array of tweets, with some nested classes including the user info and entity info (hashtags, user mentions). Here I included two elements of the array:

2014-01-03-11-03.terms.json

{
"tweets": [
    {
        "filter_level": "medium",
        "contributors": null,
        "text": "U know your ice fishing at home when ur snacks are sandwiches,chips,dips,beef jerky and all the goodies instead of just a case of beer #mom",
        "geo": null,
        "retweeted": false,
        "in_reply_to_screen_name": null,
        "truncated": false,
        "lang": "en",
        "entities": {
            "symbols": [

            ],
            "urls": [

            ],
            "hashtags": [
                {
                    "text": "mom",
                    "indices": [
                        135,
                        139
                    ]
                }
            ],
            "user_mentions": [

            ]
        },
        "in_reply_to_status_id_str": null,
        "id": 419137025376145408,
        "source": "<a href="http://twitter.com/download/iphone" rel="nofollow">Twitter for iPhone</a>",
        "in_reply_to_user_id_str": null,
        "favorited": false,
        "in_reply_to_status_id": null,
        "retweet_count": 0,
        "created_at": "Fri Jan 03 16:03:48 +0000 2014",
        "in_reply_to_user_id": null,
        "favorite_count": 0,
        "id_str": "419137025376145408",
        "place": null,
        "user": {
            "location": "",
            "default_profile": false,
            "profile_background_tile": true,
            "statuses_count": 5411,
            "lang": "en",
            "profile_link_color": "17EBCF",
            "profile_banner_url": "https://pbs.twimg.com/profile_banners/408240224/1384838946",
            "id": 408240224,
            "following": null,
            "protected": false,
            "favourites_count": 4222,
            "profile_text_color": "333333",
            "description": "It is what it is, no more, no less. Trust in the Lord. BSU Softball #5.  My whole being is happy - Psalm 16:9",
            "verified": false,
            "contributors_enabled": false,
            "profile_sidebar_border_color": "FFFFFF",
            "name": "Nicole Anne",
            "profile_background_color": "C0DEED",
            "created_at": "Wed Nov 09 05:03:58 +0000 2011",
            "default_profile_image": false,
            "followers_count": 452,
            "profile_image_url_https": "https://pbs.twimg.com/profile_images/413270299925164033/mWiJBKP2_normal.jpeg",
            "geo_enabled": true,
            "profile_background_image_url": "http://a0.twimg.com/profile_background_images/698793822/14d9ce538d96b435ad4449d5385a3ec1.jpeg",
            "profile_background_image_url_https": "https://si0.twimg.com/profile_background_images/698793822/14d9ce538d96b435ad4449d5385a3ec1.jpeg",
            "follow_request_sent": null,
            "url": null,
            "utc_offset": -32400,
            "time_zone": "Alaska",
            "notifications": null,
            "profile_use_background_image": true,
            "friends_count": 634,
            "profile_sidebar_fill_color": "DDEEF6",
            "screen_name": "NDupay",
            "id_str": "408240224",
            "profile_image_url": "http://pbs.twimg.com/profile_images/413270299925164033/mWiJBKP2_normal.jpeg",
            "listed_count": 1,
            "is_translator": false
        },
        "coordinates": null
    },
    {
        "filter_level": "medium",
        "contributors": null,
        "text": "Just watched DeBlasio shovel snow for the cameras and I have to say, his form is terrible. Looks a bit inexperienced.",
        "geo": null,
        "retweeted": false,
        "in_reply_to_screen_name": null,
        "truncated": false,
        "lang": "en",
        "entities": {
            "symbols": [

            ],
            "urls": [

            ],
            "hashtags": [

            ],
            "user_mentions": [

            ]
        },
        "in_reply_to_status_id_str": null,
        "id": 419137026458673152,
        "source": "<a href="http://twitter.com/download/iphone" rel="nofollow">Twitter for iPhone</a>",
        "in_reply_to_user_id_str": null,
        "favorited": false,
        "in_reply_to_status_id": null,
        "retweet_count": 0,
        "created_at": "Fri Jan 03 16:03:48 +0000 2014",
        "in_reply_to_user_id": null,
        "favorite_count": 0,
        "id_str": "419137026458673152",
        "place": null,
        "user": {
            "location": "",
            "default_profile": false,
            "profile_background_tile": false,
            "statuses_count": 2609,
            "lang": "en",
            "profile_link_color": "FF8000",
            "id": 163686045,
            "following": null,
            "protected": false,
            "favourites_count": 204,
            "profile_text_color": "333333",
            "description": "Love learning, Hockey #NYR, music and photography. My family is my whole life.",
            "verified": false,
            "contributors_enabled": false,
            "profile_sidebar_border_color": "EEEEEE",
            "name": "Steven Marques",
            "profile_background_color": "ACDED6",
            "created_at": "Wed Jul 07 01:26:25 +0000 2010",
            "default_profile_image": false,
            "followers_count": 56,
            "profile_image_url_https": "https://pbs.twimg.com/profile_images/378800000795958214/5e3ff928282ad692a36e941e5c5ff628_normal.jpeg",
            "geo_enabled": false,
            "profile_background_image_url": "http://abs.twimg.com/images/themes/theme18/bg.gif",
            "profile_background_image_url_https": "https://abs.twimg.com/images/themes/theme18/bg.gif",
            "follow_request_sent": null,
            "url": null,
            "utc_offset": -18000,
            "time_zone": "Eastern Time (US & Canada)",
            "notifications": null,
            "profile_use_background_image": true,
            "friends_count": 58,
            "profile_sidebar_fill_color": "F6F6F6",
            "screen_name": "SMGafanha",
            "id_str": "163686045",
            "profile_image_url": "http://pbs.twimg.com/profile_images/378800000795958214/5e3ff928282ad692a36e941e5c5ff628_normal.jpeg",
            "listed_count": 2,
            "is_translator": false
        },
        "coordinates": null
    },

Here is the Java class that the JSON file is mapped to, followed by the class mapping the JSON:

Tweets.java

public class Tweets {

private ArrayList<Tweet> tweets;

public Tweets() {
    tweets = new ArrayList<Tweet>();
}

public ArrayList<Tweet> getTweets() {
    return tweets;
}

public void setTweets(ArrayList<Tweet> tweets) {
    this.tweets = tweets;
}

public static class Tweet {

    private String text;
    @JsonProperty("source")
    private String postMethod;
    @JsonProperty("created_at")
    private String time;
    @JsonProperty("id")
    private String ID;

    public Tweet() {

    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public String getID() {
        return ID;
    }

    public void setID(String iD) {
        ID = iD;
    }

    public String getPostMethod() {
        return postMethod;
    }

    public void setPostMethod(String postMethod) {
        this.postMethod = postMethod;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }

    public class User {

        private String location;
        @JsonProperty("screen_name")
        private String user;
        @JsonProperty("time_zone")
        private String timeZone;
        @JsonProperty("description")
        private String accountDescription;

        public User(){

        }

        public String getLocation() {
            return location;
        }

        public void setLocation(String location) {
            this.location = location;
        }

        public String getUser() {
            return user;
        }

        public void setUser(String user) {
            this.user = user;
        }

        public String getTimeZone() {
            return timeZone;
        }

        public void setTimeZone(String timeZone) {
            this.timeZone = timeZone;
        }

        public String getAccountDescription() {
            return accountDescription;
        }

        public void setAccountDescription(String accountDescription) {
            this.accountDescription = accountDescription;
        }
    }
    public class Entities {

        @JsonProperty("user_mentions")
        ArrayList<UserMention> userMentions;
        @JsonProperty("hashtags")
        ArrayList<Hashtag> hashtags;

        public Entities() {
            userMentions = new ArrayList<UserMention>();
            hashtags = new ArrayList<Hashtag>();                
        }

        public ArrayList<UserMention> getUserMentions() {
            return userMentions;
        }

        public int getNumUserMentions() {
            return userMentions.size();
        }

        public UserMention getUserMention(int index) {
            return userMentions.get(index);
        }

        public void setUserMentions(ArrayList<UserMention> userMentions

Answer 1

Once again, just like in the case with tweets, you're not loading data to 'user' object. Instead of:

user = tweet.new User();

You should use:

user = tweet.getUser();

You're also missing the following in your Tweet class:

@JsonProperty("user")
private User user;
public User getUser() { return user; }

I don't know how you've generated your Tweets.java file, but it doesn't seem to be complete. Consider using http://www.jsonschema2pojo.org/ to re-generate it.