Lombok notes

Russell Bateman
April 2022


Fabrication of a bean 
import lombok.Data;

@Data
public class Car
{
  private String brand;
  private String model;
  private int    year;
}

Fabrication of a builder 
import lombok.Builder;

@Builder
public class Car
{
  private String brand;
  private String model;
  private int year;

  public static void main( String[] args )
  {
     Car myCamaro = Car.builder()
                       .brand( "Chevrolet" )
                       .model( "Camaro" )
                       .year( 2022 )
                       .build();
  }
}

Fabrication of a builder with @NonNull...

...that throws an error if anything required is missing. 

import lombok.Builder;
import lombok.NonNull;

@Builder
public class DetailedCar
{
  @NonNull private String brand;
  @NonNull private String model;
  @NonNull private int    year;
  @NonNull private String engineCode;
  @NonNull private String engineType;
           private String requiredFuel;
           private String fuelSystem;
           private String maxHorsePower;
           private String maxTorque;
           private float fuelCapacity;

  public static void main( String[] args )
  {
     Car myCamaro = Car.builder()
                       .brand( "Chevrolet" )
                       .model( "Camaro" )
                       .year( 2022 )
                       .build();
  }
}

If, as above, engineCode and/or engineType are missing from the builder invocation, an Exception will be thrown: 

Exception in thread "main" java.lang.NullPointerException: engineCode is marked non-null but is null

Inheritance...

...that throws an error if anything required is missing. 

import lombok.Data;
import lombok.ToString;
import lombok.EqualsAndHashCode;

@Data
@ToString( callSuper = true )
@EqualsAndHashCode( callSuper = true )

public class Car extends MotorVehicle
{
  private String brand;
  private String model;
  private int    year;

  ...
}