JSON to Java POJO

{"order_id": 7, "items": [{"sku": "a-1", "qty": 2}]}

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.List;

public class Order {
    @JsonProperty("order_id")
    private long orderId;
    @JsonProperty("items")
    private List<Item> items;

    public long getOrderId() { return orderId; }
    public void setOrderId(long value) { this.orderId = value; }

    public List<Item> getItems() { return items; }
    public void setItems(List<Item> value) { this.items = value; }

    public static class Item {
        @JsonProperty("sku")
        private String sku;
        @JsonProperty("qty")
        private long qty;

        public String getSku() { return sku; }
        public void setSku(String value) { this.sku = value; }

        public long getQty() { return qty; }
        public void setQty(long value) { this.qty = value; }
    }
}

Two object shapes in, two classes out: Order carries the list and Item is its element type. The wire key order_id lives in the annotation while the field reads as orderId with a getter and setter pair.

{"order_id": 4102, "items": [{"sku": "b-7", "qty": 1}]}

import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.List;

public record Root(
    @JsonProperty("order_id") long orderId,
    @JsonProperty("items") List<Item> items
) {
    public record Item(
        @JsonProperty("sku") String sku,
        @JsonProperty("qty") long qty
    ) {}
}

The record form of the same shape: components replace fields, each annotation moves onto its component, and no accessor methods appear — a record derives accessors, equals, hashCode and toString itself, so only the nested Item record rides in the body.

{"order_id": 7}

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

@Data
public class Root {
    @JsonProperty("order_id")
    private long orderId;
}

One @Data annotation stands in for every accessor — Lombok writes them during compilation, so the generated source lists only the annotated fields.

{"class": "economy", "new": true}

import com.fasterxml.jackson.annotation.JsonProperty;

public class Root {
    @JsonProperty("class")
    private String rootClass;
    @JsonProperty("new")
    private boolean rootNew;

    public String getRootClass() { return rootClass; }
    public void setRootClass(String value) { this.rootClass = value; }

    public boolean getRootNew() { return rootNew; }
    public void setRootNew(boolean value) { this.rootNew = value; }
}

class and new are reserved words in Java, so the fields become rootClass and rootNew and a chip reports each rename — the annotations keep deserialization reading the original keys.