How to use @RequestParam with nested objects

I need to convert 2-D array comes from JSON to a string. I just need to manipulate that value.

There is an example of the JSON:

https://en.wikipedia.org/wiki/GeoJSON

@RequestMapping is the way to manipulate value that comes from REST. But i dont know how to do it for nested object.

    @ResponseBody
    public GeoJson saveData(@RequestParam {What i need}...) throws IOException{
        return geoJSONRepository.save(geoJson);
    }

GeoJson class:

@Entity
public class GeoJson {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long id;
    private String type;
    @OneToMany(cascade = CascadeType.ALL)
    @ToString.Exclude
    private List<Feature> features = new ArrayList<Feature>();
    public GeoJson() {
    }
}

Feature class:

@Entity
public class Feature {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long fId;
    private String type;
    @OneToOne(cascade = CascadeType.ALL)
    private Properties properties;
    @OneToOne(cascade = CascadeType.ALL)
    private Geometry geometry;
}

Properties class:

@Entity
public class Properties {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "pId", nullable = false)
    private Long pId;
    @Column(name = "property_type")
    private String type;
}

Geometry class:

@Entity
public class Geometry {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "gId", nullable = false)
    private Long gId;
    private String type;
    private String coordinates; //2-d coordinates value

}