Deserializing JSON into Object with list attribute

Question

I have two objects, Product with OneToMany self reference and OneToMany relationship to Image.

From a Rest API, I need to create CRUD services. I created the following services:

Add new Product: {"name":"chair", "description":"red chair"}

@Path("/product/add")
@Consumes("application/json")

Add new Child Product: {"name":"table", "description":"red table"}

@Path("/product/{id}/addChild")
@Consumes("application/json")

Add Image to Product:

/product/1/image/add

{"type":"PNG"}

@Path("/product/{id}/image/add")
@Consumes("application/json")

Update Product:

/product/update/1

{"name":"chair", "description":"blue chair"}

@Path("/product/update/{id}")
@Consumes("application/json")

Update Image:

/image/update/1

{"type":"JPEG"}

@Path("/image/update/{id}")
@Consumes("application/json")

Delete Product:

/product/delete/1

@DELETE
@Path("/product/delete/{id}")

Delete Image:

/image/delete/1

@DELETE
@Path("/image/delete/{id}")

Product.java:

@Entity
@Table
public class Product implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@Column(name = "ID")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer productId;

@Column(name = "NAME")
private String name;

@Column(name = "DESCRIPTION")
private String description;

@OneToMany(cascade=CascadeType.ALL)
@JoinColumn(name="PRODUCT_ID")
private List<Image> images;

@OneToMany(cascade=CascadeType.ALL, mappedBy="parent")
private List<Product> children;

@ManyToOne
@JoinColumn(name = "PARENT_PRODUCT_ID")
private Product parent;   

Image.java:

@Entity
@Table
public class Image implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@Column(name = "ID")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer imageId;

@Column(name = "TYPE")
private String type;

@ManyToOne
@JoinColumn(name = "PRODUCT_ID", nullable = false)
private Product product;

When I try to add a Product with a Image, I got an error:

{"name":"bucket", "description":"red bucket", "images":{"type":"jpeg"} }

Can not deserialize instance of java.util.ArrayList out of START_OBJECT token at [Source: org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$UnCloseableInputStream@3c9786ad; line: 2, column: 27] (through reference chain: br.com.model.Product["images"])

Need help to:

1. Add with one JSON a Product with Images;
2. The way of adding child products is correct (using PathParam)?

Answer 1

Your images property in json string is not an array/list, it is an object. It should also be encapsulated with [] to be so, not only with {} . That's why the deserialization fails.