Parse inconsistent JSON to POJO using retrofit

I have a JSON response which contains multiple JSON object in it. Sometimes these JsonObject contains data and sometimes these JsonObject contain an empty string. So when I am parsing this JSON response to POJO using retrofit gson converter, it's throwing "java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $". I am not sure how to handle such dynamic response.

My JSON:

{
        "assetDetails": {
            "id": "0-0-175244",
            "rating": 5,
            "duration": 3538,
            "on_air": "true",
            "content_owner": "ghuiiio",
            "business_type": "premium_downloadable",
            "age_rating": "A",
            "title": "QWERTY",
            "actors": [
                "ABC",
                "PQR"
            ],
            "asset_type": 0,
            "original_title": "QWERTY",
            "directors": [
                "jgdhisl"
            ],
            "asset_subtype": "movie",
            "drm_key_id": "1cba26eb-9d76-4275-9a5c-c651640dc929",
            "subtitle_lang": [
                "en"
            ],
            "end_credits_start_s": "00:00:56",
            "orderid": 0,
            "extended": {
                "seo_title": "QWERTY",
                "broadcast_state": "",
                "music_directors": []
            },
            "season_details": "",
            "description": "XYZ",
            "genres": [
                {
                    "id": "Thriller",
                    "value": "Thriller"
                }
            ],
            "release_date": "2020-06-27T00:00:00",
            "subtitle_languages": [
                "en"
            ],
            "languages": [
                "hi"
            ],
            "audio_languages": [
                "hi"
            ]
    }
}

POJO:

public class PlaybackDetails{
	@SerializedName("assetDetails")
	private AssetDetails assetDetails;

	@SerializedName("watchHistoryDetails")
	private WatchHistoryDetails watchHistoryDetails;

	@SerializedName("trailerDetails")
	private Object trailerDetails;

	@SerializedName("keyOsDetails")
	private KeyOsDetails keyOsDetails;

	@SerializedName("entitlement")
	private Entitlement entitlement;

	@SerializedName("adDetails")
	private AdDetails adDetails;

	@SerializedName("showDetails")
	private ShowDetails showDetails;

	
	public void setAssetDetails(AssetDetails assetDetails){
		this.assetDetails = assetDetails;
	}

	public AssetDetails getAssetDetails(){
		return assetDetails;
	}

	public void setWatchHistoryDetails(WatchHistoryDetails watchHistoryDetails){
		this.watchHistoryDetails = watchHistoryDetails;
	}

	public WatchHistoryDetails getWatchHistoryDetails(){
		return watchHistoryDetails;
	}

	public void setTrailerDetails(Object trailerDetails){
		this.trailerDetails = trailerDetails;
	}

	public Object getTrailerDetails(){
		return trailerDetails;
	}

	public void setKeyOsDetails(KeyOsDetails keyOsDetails){
		this.keyOsDetails = keyOsDetails;
	}

	public KeyOsDetails getKeyOsDetails(){
		return keyOsDetails;
	}

	public void setEntitlement(Entitlement entitlement){
		this.entitlement = entitlement;
	}

	public Entitlement getEntitlement(){
		return entitlement;
	}

	public void setAdDetails(AdDetails adDetails){
		this.adDetails = adDetails;
	}

	public AdDetails getAdDetails(){
		return adDetails;
	}

	public void setShowDetails(ShowDetails showDetails){
		this.showDetails = showDetails;
	}

	public ShowDetails getShowDetails(){
		return showDetails;
	}

	@Override
 	public String toString(){
		return 
			"PlaybackDetails{" + 
			"convivaDetails = '" + convivaDetails + '\'' + 
			",assetDetails = '" + assetDetails + '\'' + 
			",watchHistoryDetails = '" + watchHistoryDetails + '\'' + 
			",trailerDetails = '" + trailerDetails + '\'' + 
			",keyOsDetails = '" + keyOsDetails + '\'' + 
			",entitlement = '" + entitlement + '\'' + 
			",adDetails = '" + adDetails + '\'' + 
			",showDetails = '" + showDetails + '\'' + 
			"}";
		}
}

    public class AssetDetails{
    
    	@SerializedName("asset_subtype")
    	private String assetSubtype;
    
    	@SerializedName("audio_languages")
    	private List<String> audioLanguages;
    
    	@SerializedName("subtitle_languages")
    	private List<String> subtitleLanguages;
    
    	@SerializedName("rating")
    	private int rating;
    
    	@SerializedName("description")
    	private String description;
    
    	@SerializedName("title")
    	private String title;
    
    	@SerializedName("drm_key_id")
    	private String drmKeyId;
    
    	@SerializedName("extended")
    	private Extended extended;
    
    	@SerializedName("duration")
    	private int duration;
    
    	@SerializedName("episode_number")
    	private int episodeNumber;
    
    	@SerializedName("video_url")
    	private VideoUrl videoUrl;
    
    	@SerializedName("subtitle_lang")
    	private List<String> subtitleLang;
    
    	@SerializedName("genres")
    	private List<GenresItem> genres;
    
    	@SerializedName("business_type")
    	private String businessType;
    
    	@SerializedName("asset_type")
    	private int assetType;
    
    	@SerializedName("tvshow")
    	private String tvshow;
    
    	@SerializedName("season")
    	private String season;
    
    	@SerializedName("id")
    	private String id;
    
    	@SerializedName("skip_available")
    	private SkipAvailable skipAvailable;
    
    	@SerializedName("cover_image")
    	private String coverImage;
    
    	@SerializedName("slug")
    	private String slug;
    
    	@SerializedName("season_details")
    	private SeasonDetails seasonDetails;
    
    	@SerializedName("original_title")
    	private String originalTitle;
    
    	@SerializedName("is_drm")
    	private int isDrm;
    
    	@SerializedName("languages")
    	private List<String> languages;
    
    	@SerializedName("list_image")
    	private String listImage;
    
    	@SerializedName("age_rating")
    	private String ageRating;
    
    	@SerializedName("orderid")
    	private int orderid;
    
    	@SerializedName("image_url")
    	private String imageUrl;
    
    	@SerializedName("end_credits_start_s")
    	private String endCreditsStartS;
    
    	@SerializedName("content_owner")
    	private String contentOwner;
    
    	@SerializedName("tags")
    	private List<String> tags;
    
    	@SerializedName("channels")
    	private List<ChannelsItem> channels;
    
    	@SerializedName("web_url")
    	private String webUrl;
    
    	@SerializedName("release_date")
    	private String releaseDate;
    
    	public void setAssetSubtype(String assetSubtype){
    		this.assetSubtype = assetSubtype;
    	}
    
    	public String getAssetSubtype(){
    		return assetSubtype;
    	}
    
    	public void setAudioLanguages(List<String> audioLanguages){
    		this.audioLanguages = audioLanguages;
    	}
    
    	public List<String> getAudioLanguages(){
    		return audioLanguages;
    	}
    
    	public void setSubtitleLanguages(List<String> subtitleLanguages){
    		this.subtitleLanguages = subtitleLanguages;
    	}
    
    	public List<String> getSubtitleLanguages(){
    		return subtitleLanguages;
    	}
    
    	public void setRating(int rating){
    		this.rating = rating;
    	}
    
    	public int getRating(){
    		return rating;
    	}
    
    	public void setDescription(String description){
    		this.description = description;
    	}
    
    	public String getDescription(){
    		return description;
    	}
    
    	public void setTitle(String title){
    		this.title = title;
    	}
    
    	public String getTitle(){
    		return title;
    	}
    
    	public void setDrmKeyId(String drmKeyId){
    		this.drmKeyId = drmKeyId;
    	}
    
    	public String getDrmKeyId(){
    		return drmKeyId;
    	}
    
    	public void setExtended(Extended extended){
    		this.extended = extended;
    	}
    
    	public Extended getExtended(){
    		return extended;
    	}
    
    	public void setDuration(int duration){
    		this.duration = duration;
    	}
    
    	public int getDuration(){
    		return duration;
    	}
    
    	public void setEpisodeNumber(int episodeNumber){
    		this.episodeNumber = episodeNumber;
    	}
    
    	public int getEpisodeNumber(){
    		return episodeNumber;
    	}
    
    	public void setVideoUrl(VideoUrl videoUrl){
    		this.videoUrl = videoUrl;
    	}
    
    	public VideoUrl getVideoUrl(){
    		return videoUrl;
    	}
    
    	public void setSubtitleLang(List<String> subtitleLang){
    		this.subtitleLang = subtitleLang;
    	}
    
    	public List<String> getSubtitleLang(){
    		return subtitleLang;
    	}
    
    	public void setGenres(List<GenresItem> genres){
    		this.genres = genres;
    	}
    
    	public List<GenresItem> getGenres(){
    		return genres;
    	}
    
    	public void setBusinessType(String businessType){
    		this.businessType = businessType;
    	}
    
    	public String getBusinessType(){
    		return businessType;
    	}
    
    	public void setAssetType(int assetType){
    		this.assetType = assetType;
    	}
    
    	public int getAssetType(){
    		return assetType;
    	}
    
    	public void setTvshow(String tvshow){
    		this.tvshow = tvshow;
    	}
    
    	public String getTvshow(){
    		return tvshow;
    	}
    
    	public void setSeason(String season){
    		this.season = season;
    	}
    
    	public String getSeason(){
    		return season;
    	}
    
    	public void setId(String id){
    		this.id = id;
    	}
    
    	public String getId(){
    		return id;
    	}
    
    	public void setSkipAvailable(SkipAvailable skipAvailable){
    		this.skipAvailable = skipAvailable;
    	}
    
    	public SkipAvailable getSkipAvailable(){
    		return skipAvailable;
    	}
    
    	public void setCoverImage(String coverImage){
    		this.coverImage = coverImage;
    	}
    
    	public String getCoverImage(){
    		return coverImage;
    	}
    
    	public void setSlug(String slug){
    		this.slug = slug;
    	}
    
    	public String getSlug(){
    		return slug;
    	}
    
    	public void setSeasonDetails(SeasonDetails seasonDetails){
    		this.seasonDetails = seasonDetails;
    	}
    
    	public SeasonDetails getSeasonDetails(){
    		return seasonDetails;
    	}
    
    	public void setOriginalTitle(String originalTitle){
    		this.originalTitle = originalTitle;
    	}
    
    	public String getOriginalTitle(){
    		return originalTitle;
    	}
    
    	public void setIsDrm(int isDrm){
    		this.isDrm = isDrm;
    	}
    
    	public int getIsDrm(){
    		return isDrm;
    	}
    
    	public void setLanguages(List<String> languages){
    		this.languages = languages;
    	}
    
    	public List<String> getLanguages(){
    		return languages;
    	}
    
    	public void setListImage(String listImage){
    		this.listImage = listImage;
    	}
    
    	public String getListImage(){
    		return listImage;
    	}
    
    	public void setAgeRating(String ageRating){
    		this.ageRating = ageRating;
    	}
    
    	public String getAgeRating(){
    		return ageRating;
    	}
    
    	public void setOrderid(int orderid){
    		this.orderid = orderid;
    	}
    
    	public int getOrderid(){
    		return orderid;
    	}
    
    	public void setImageUrl(String imageUrl){
    		this.imageUrl = imageUrl;
    	}
    
    	public String getImageUrl(){
    		return imageUrl;
    	}
    
    	public void setEndCreditsStartS(String endCreditsStartS){
    		this.endCreditsStartS = endCreditsStartS;
    	}
    
    	public String getEndCreditsStartS(){
    		return endCreditsStartS;
    	}
    
    	public void setContentOwner(String contentOwner){
    		this.contentOwner = contentOwner;
    	}
    
    	public String getContentOwner(){
    		return contentOwner;
    	}
    
    	public void setTags(List<String> tags){
    		this.tags = tags;
    	}
    
    	public List<String> getTags(){
    		return tags;
    	}
    
    	public void setChannels(List<ChannelsItem> channels){
    		this.channels = channels;
    	}
    
    	public List<ChannelsItem> getChannels(){
    		return channels;
    	}
    
    	public void setWebUrl(String webUrl){
    		this.webUrl = webUrl;
    	}
    
    	public String getWebUrl(){
    		return webUrl;
    	}
    
    	public void setReleaseDate(String releaseDate){
    		this.releaseDate = releaseDate;
    	}
    
    	public String getReleaseDate(){
    		return releaseDate;
    	}
    
    	@Override
     	public String toString(){
    		return 
    			"AssetDetails{" + 
    			"asset_subtype = '" + assetSubtype + '\'' + 
    			",audio_languages = '" + audioLanguages + '\'' + 
    			",subtitle_languages = '" + subtitleLanguages + '\'' + 
    			",rating = '" + rating + '\'' + 
    			",description = '" + description + '\'' + 
    			",title = '" + title + '\'' + 
    			",drm_key_id = '" + drmKeyId + '\'' + 
    			",extended = '" + extended + '\'' + 
    			",duration = '" + duration + '\'' + 
    			",episode_number = '" + episodeNumber + '\'' + 
    			",video_url = '" + videoUrl + '\'' + 
    			",subtitle_lang = '" + subtitleLang + '\'' + 
    			",genres = '" + genres + '\'' + 
    			",business_type = '" + businessType + '\'' + 
    			",asset_type = '" + assetType + '\'' + 
    			",tvshow = '" + tvshow + '\'' + 
    			",season = '" + season + '\'' + 
    			",id = '" + id + '\'' + 
    			",skip_available = '" + skipAvailable + '\'' + 
    			",cover_image = '" + coverImage + '\'' + 
    			",slug = '" + slug + '\'' + 
    			",season_details = '" + seasonDetails + '\'' + 
    			",original_title = '" + originalTitle + '\'' + 
    			",is_drm = '" + isDrm + '\'' + 
    			",languages = '" + languages + '\'' + 
    			",list_image = '" + listImage + '\'' + 
    			",age_rating = '" + ageRating + '\'' + 
    			",orderid = '" + orderid + '\'' + 
    			",image_url = '" + imageUrl + '\'' + 
    			",end_credits_start_s = '" + endCreditsStartS + '\'' + 
    			",content_owner = '" + contentOwner + '\'' + 
    			",tags = '" + tags + '\'' + 
    			",channels = '" + channels + '\'' + 
    			",web_url = '" + webUrl + '\'' + 
    			",release_date = '" + releaseDate + '\'' + 
    			"}";
    		}
    }

In the above JSON season_details can be a JSONObject or empty.

You can use custom deserializer to inspect if the value is a real object and decide what to do if it is not.

For example (to be used for any type):

public class StringOrObjectDeSerializer<T> implements JsonDeserializer<T> {
	// deserializer NOT registered with this Gson to prevent recursion!
	private final Gson innerGson = new Gson();

	@Override
	public T deserialize(JsonElement json, Type typeOfT, 
            JsonDeserializationContext context)
	        throws JsonParseException {
		if (json.isJsonObject()) {
			return innerGson.fromJson(json, typeOfT);
		}
        // null or some other default value for non-json-objects
		return null;
	}
}

Just register it before using, like:

Gson gson = new GsonBuilder()
    .registerTypeAdapter(SeasonDetail.class, new StringOrObjectDeSerializer<>())
    .create();

If you need to know how to register it with Retrofit, see this post