public class SecuritiesMarketData {

    @SerializedName("marketdata")
    @Expose
    private Marketdata marketdata;

    public Marketdata getMarketdata() {
        return marketdata;
    }

    public void setMarketdata(Marketdata marketdata) {
        this.marketdata = marketdata;
    }

    public class Marketdata {

        @SerializedName("columns")
        @Expose
        private List<String> columns = null;
        //@SerializedName("data")
        //@Expose
        //private List<List<String>> data = null;

        public List<String> getColumns() {
            return columns;
        }

        public void setColumns(List<String> columns) {
            this.columns = columns;
        }

    }

}