Immutable Lombok annotated class with Jackson

Question

What is the preferred way to create class that is

• Immutable
• Can be serialized/deserialized with Jackson
• Human-readable and with low level of

Answer 1

Try the following set of annotations for your pojo:

@Value
@NoArgsConstructor(force = true, access = AccessLevel.PRIVATE)
@AllArgsConstructor

Answer 2

You can use Lombok's @Builder annotation to generate a builder for your immutable POJO class. But making the Lombok-generated builder usable by Jackson's deserialization is somewhat tricky.

• You need to annotate your POJO class with @JsonDeserialize(builder = ...) to tell Jackson which is the builder class to use.
• You need to annotate the builder class with @JsonPOJOBuilder(withPrefix = "") to tell Jackson that its setter-methods do not start with with.

Example:

An immutable POJO class:

@Data
@Builder(builderClassName = "PointBuilder")
@JsonDeserialize(builder = Point.PointBuilder.class)
public class Point {

    private final int x;

    private final int y;

    @JsonPOJOBuilder(withPrefix = "")
    public static class PointBuilder {
        // Lombok will add constructor, setters, build method
    }
}

Here is a JUnit test to verify the serialization/deserialization:

public class PointTest extends Assert {

    private ObjectMapper objectMapper = new ObjectMapper();

    @Test
    public void testSerialize() throws IOException {
        Point point = new Point(10, 20);
        String json = objectMapper.writeValueAsString(point);
        assertEquals("{\"x\":10,\"y\":20}", json);
    }

    @Test
    public void testDeserialize() throws IOException {
        String json = "{\"x\":10,\"y\":20}";
        Point point = objectMapper.readValue(json, Point.class);
        assertEquals(new Point(10, 20), point);
    }
}

Answer 3

The simplest way to configure immutable class for Jackson is to use lombok annotation: @Value and @Jacksonized:

    @Jacksonized
    @Builder
    @Value
    class Foo {

        
    }