What is the @NoArgsConstructor annotation in Lombok?
What is Lombok?
Project Lombok is a Java library that helps to reduce the
We can easily add Lombok to the project as one of the dependencies.
For a Gradle project, add the following two lines to the dependencies section of the build.gradle file:
compileOnly 'org.projectlombok:lombok:1.18.22'
annotationProcessor 'org.projectlombok:lombok:1.18.22'
For a Maven project, add the following lines to the dependencies section of the pom.xml file:
<dependencies><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.22</version><scope>provided</scope></dependency></dependencies>
@NoArgsConstructor annotation
The @NoArgsConstructor annotation is used to generate the no-argument constructor for a class. In this case, the class consists of final fields. Using this annotation makes the compiler throw a compile-time error. To overcome this, the annotation takes a parameter called force which, when set to true, initializes the final fields 0 or false or null.
Note: A no-argument constructor is a constructor with no parameters.
Code
The following code shows how the annotation reduces writing the no-arg constructor to a single annotation:
import lombok.NoArgsConstructor;public class Main {static class Person{private int age;public Person() {}}@NoArgsConstructorstatic class NewPerson{private int age;}}
Explanation
In the above code, we have two classes, Person and NewPerson. A no-arg constructor is written for the Person class in line 8.
The NewPerson class is annotated with @NoArgsConstructor annotation. The annotation generates the no-arg constructor for us.
