Cannot construct instance of `class name` (although at least on Creator exists)

Hi you need to write custom deserializer as it not able to parse String (fromDate and toDate) to Date

{ "fromDate":"2019-03-09", "toDate":"2019-03-10" }

this link has a tutorial to get started with custom deserializer https://www.baeldung.com/jackson-deserialization

Deserializer could be written like this.

public class CustomDateDeserializer extends StdDeserializer<Date> {

private static SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");

public CustomDateDeserializer() {
    this(null);
}

public CustomDateDeserializer(Class<?> vc) {
    super(vc);
}

@Override
public Date deserialize(JsonParser jsonparser, DeserializationContext context) throws IOException {
    String date = jsonparser.getText();
    try {
        return formatter.parse(date);
    } catch (ParseException e) {
        throw new RuntimeException(e);
    }
}}

You can register the deserializer at Class itself like this.

@JsonDeserialize(using = ItemDeserializer.class)
public class Item {  ...}

Or either you can register custom deserializer manually like this

ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addDeserializer(Item.class, new ItemDeserializer());
mapper.registerModule(module);

You need a constructor with all parameters:

public SampleRequest(String fromDate, String toDate) {

    this.fromDate = fromDate;
    this.toDate = toDate;

}

Or using @AllArgsConstructor or @Data from lombok.

In my case i was missing the No Args contructor

@Data
@AllArgsConstructor
@NoArgsConstructor

for those who are no using Lombok do add no args constructor in the mapping pojo

public ClassA() {
        super();
        // TODO Auto-generated constructor stub
    }

also dont forget to add the Bean of Restemplate in main file if you are using the same