Code Recipes Blog

In all my previous posts under Lombok, I used Pojo classes as an example.

All these Pojo classes are mutable since they have setter and getter method.

In this post, I will show with example how to create an immutable class.

To create an immutable class, we annotate a Pojo class with “@Value” annotation and we declared the fields as private final.

The “@Value” annotation is applied at the class level as shown below

Person class

package package23;

import lombok.Value;

@Value
public class Person {
    private final String firstName;
    private final String middleName;
    private final String lastName;
    private final float salary;
}

In the above Pojo class “Person”.

It is annotated with “@Value” annotation.

All the fields are private and final.

In addition to making the Pojo class as immutable, it also generates “toString”, “hashCode”, and “equals” methods.

It also generates a constructor with all fields.

Below is the main class that shows the usage.

Main class

package package23;

public class Example23 {
    public static void main(String[] args) {
        Person person = new Person("Ellis", "M", "Robertson", 1000.50f);
        System.out.println(person);
    }
}