Question

When I create a Data transfer Object (DTO) which I use to store user input data to manager layer, I have a doubt that I’m doing it in correct way.

For example

Scenario one

public class Person{

    private String name;
    private int age;  // primitive type
    private double weight; // primitive type

}

Scenario 2

public class Person{

    private String name;
    private Integer age;
    private Double weight;

}

in this case what is the best scenario that I can use and what are the factors that I should think about when decide on each scenarios. Kindly advice me.

Answer 1

If you can use a primitive type, I would use a primitive type. Not just for performance reasons but to make it clear that null is not a valid value.

If you have a value which can be null, use a wrapper.

Also if you can make the fields final I would do so as well as this avoids questions of mutability and thread safety.