Lombok @builder on a class that extends another class

Question

I have two classes Child extends Parent. I need to put @Builder annotation on the classes such that I do not need to create the builder my self.

package jerry;// Internal compiler error: java.lang.NullPointerException

import lombok.AllArgsConstructor;
import lombok.Builder;

@AllArgsConstructor(onConstructor=@__(@Builder))
public class Child extends Parent { 
//Multiple markers at this line
//  - Implicit super constructor Parent() is undefined. Must explicitly invoke another constructor
//  - overrides java.lang.Object.toString

   private String a;
   private int b;
   private boolean c;

}


@Builder
public class Parent {
    private double d;
    private float e;
}

I need to be able to build child instance such that

Child child = Child.builder().a("aVal").b(1000).c(true).d(10.1).e(20.0F).build();

But so far I am getting the errors mentioned in side that code comments. Can any one point me to the right direction how to achieve it with lombok or any other similar library ?

Sub-question

Why does @AllArgsConstructor(onConstructor=@__(@Autowired)) compile but @AllArgsConstructor(onConstructor=@__(@Builder)) does not?

Answer 1

Since release 1.18.2 lombok includes the new experimental @SuperBuilder. It supports fields from superclasses (also abstract ones). With it, the solution is as simple as this:

@SuperBuilder
public class Child extends Parent {
   private String a;
   private int b;
   private boolean c;
}

@SuperBuilder
public class Parent {
    private double d;
    private float e;
}

Child instance = Child.builder().b(7).e(6.3).build();

Update 2019-10-09: If you use IntelliJ, you need at least version 0.27 of the IntelliJ Lombok plugin to use @SuperBuilder.

PS: @AllArgsConstructor(onConstructor=@__(@Builder)) does not work because @Builder is an annotation-processing annotation that lombok translates to code during compilation. Generating and then translating new lombok annotation would require several iterations of annotation processing, and lombok does not support that. @Autowired, in contrast, is a regular Java annotation available at runtime.