how to Call super constructor in Lombok

Question

I have a class    Value  NonFinal public class A       int x      int y      I have another class B   Value public class B extends A       int z      lombok is throwing error saying it cant find A   constructor  explicitly call it what i want lombok to do is to give annotation to class b such that  it generates the following code   public class B extends A       int z      public B  int x  int y  int z            super  x   y            this z   z            Do we have an annotation to do that in Lombok

User · Answer

This is not possible in Lombok  Although it would be a really nice feature  it requires resolution to find the constructors of the super class  The super class is only known by name the moment Lombok gets invoked  Using the import statements and the classpath to find the actual class is not trivial  And during compilation you cannot just use reflection to get a list of constructors   It is not entirely impossible but the results using resolution in val and  ExtensionMethod have taught us that is it hard and error-prone   Disclosure  I am a Lombok developer

User · Answer

If child class has more members  than parent  it could be done not very clean  but short way    Data  RequiredArgsConstructor  EqualsAndHashCode callSuper   true   ToString callSuper   true  public class User extends BaseEntity       private  NonNull String fullName      private  NonNull String email                public User Integer id  String fullName  String email                  this fullName  email                 this id   id            Data  AllArgsConstructor abstract public class BaseEntity      protected Integer id      public boolean isNew           return id    null

User · Answer

Lombok does not support that also indicated by making any  Value annotated class final  as you know by using  NonFinal    The only workaround I found is to declare all members final yourself and use the  Data annotation instead  Those subclasses need to be annotated by  EqualsAndHashCode and need an explicit all args constructor as Lombok doesn t know how to create one using the all args one of the super class    Data public class A       private final int x      private final int y      Data  EqualsAndHashCode callSuper   true  public class B extends A       private final int z       public B int x  int y  int z            super x  y           this z   z            Especially the constructors of the subclasses make the solution a little untidy for superclasses with many members  sorry

User · Answer

Lombok Issue  78 references this page https   www donneo de 2015 09 16 lomboks-builder-annotation-and-inheritance  with this lovely explanation     AllArgsConstructor  public class Parent           private String a      public class Child extends Parent     private String b      Builder   public Child String a  String b       super a       this b   b                   As a result you can then use the generated builder like this   Child builder   a  testA   b  testB   build           The official documentation explains this  but it doesn   t explicitly point out that you can facilitate it in this way    I also found this works nicely with Spring Data JPA

User · Answer

Version 1 18 of Lombok introduced the  SuperBuilder annotation  We can use this to solve our problem in a simpler way   You can refer to https   www baeldung com lombok-builder-inheritance lombok-builder-and-inheritance-3   so in your child class  you will need these annotations    Data  SuperBuilder  NoArgsConstructor  EqualsAndHashCode callSuper   true    in your parent class     Data  SuperBuilder  NoArgsConstructor

User · Answer

for superclasses with many members I would suggest you to use  Delegate   Data public class A        Delegate public class AInner          private final int x          private final int y            Data  EqualsAndHashCode callSuper   true  public class B extends A       private final int z       public B A AInner a  int z            super a           this z   z

User · Answer

As an option you can use com fasterxml jackson databind ObjectMapper to initialize a child class from parent public class A       int x      int y     public class B extends A       int z     ObjectMapper MAPPER   new ObjectMapper      it s configurable MAPPER configure  DeserializationFeature FAIL ON UNKNOWN PROPERTIES  false    MAPPER configure  SerializationFeature FAIL ON EMPTY BEANS  false       Then wherever you need to initialize child from parent  A parent   new A x  y   B child   MAPPER convertValue  parent  B class   child setZ z    You can still use any lombok annotations on A and B if you need

[java] how to Call super constructor in Lombok

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