Pass data with multiple attributes in one shot from client to server, to avoid multiple calls to remote server.
## Explanation
Real world example
> We need to fetch information about customers from remote database. Instead of querying the attributes one at a time, we use DTOs to transfer all the relevant attributes in a single shot.
In plain words
> Using DTO relevant information can be fetched with a single backend query.
Wikipedia says
> In the field of programming a data transfer object (DTO) is an object that carries data between processes. The
motivation for its use is that communication between processes is usually done resorting to remote interfaces
(e.g., web services), where each call is an expensive operation. Because the majority of the cost of each call is
related to the round-trip time between the client and the server, one way of reducing the number of calls is to use an
object (the DTO) that aggregates the data that would have been transferred by the several calls, but that is served by
one call only.
**Programmatic Example**
Let's first introduce our simple customer DTO class.
```java
public class CustomerDto {
private final String id;
private final String firstName;
private final String lastName;
public CustomerDto(String id, String firstName, String lastName) {
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
}
public String getId() {
return id;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
}
```
Customer resource class acts as the server for customer information.
