Lombok @Builder and JPA Default constructor
If the annotations lombok.Tolerate on constructor and javax.validation.constraints.NotNull on some property are used at the same time, sonarqube will mark it as a critical error: PROPERTY is marked "javax.validation.constraints.NotNull" but is not initialized in this constructor.
If the project uses SpringData with JPA, it can be solved using org.springframework.data.annotation.PersistenceConstructor (Spring annotation, not JPA!)
Then, in combination with Lombok, annotations will be like this:
@RequiredArgsConstructor(onConstructor = @__(@PersistenceConstructor))
For Lombok builder you also need to add:
@Builder
@AllArgsConstructor
It seems that the annotations order is important here, using the same annotations, but different orders, you can have the code working, or not.
Here is a non working example:
@AllArgsConstructor
@Builder
@Data
@Entity
@EqualsAndHashCode
@NoArgsConstructor
@RequiredArgsConstructor
@Table
@ToString
public class Person implements Serializable {
private String name;
}
And this is a working example:
@Builder
@Data
@Entity
@EqualsAndHashCode
@AllArgsConstructor
@NoArgsConstructor
@RequiredArgsConstructor
@Table
@ToString
public class Person implements Serializable {
private String name;
}
So be sure to have the @Builder annotation at the very top position, in my case I encountered this error because I wanted to sort annotations alphabetically.
You can also solve it explicitly with @Data @Builder @NoArgsConstructor @AllArgsConstructor
combined on the class definition.
Updated
Based on the feedback and John's answer I have updated the answer to no longer use @Tolerate
or @Data
and instead we create accessors and mutators via @Getter
and @Setter
, create the default constructor via @NoArgsConstructor
, and finally we create the all args constructor that the builder requires via @AllArgsConstructor
.
Since you want to use the builder pattern I imagine you want to restrict visibility of the constructor and mutators methods.
To achieve this we set the visibility to package private
via the access
attribute on the @NoArgsConstructor
and @AllArgsConstructor
annotations and the value
attribute on the @Setter
annotation.
Important
Remember to properly override toString
, equals
, and hashCode
.
See the following posts by Vlad Mihalcea for details:
- the-best-way-to-implement-equals-hashcode-and-tostring-with-jpa-and-hibernate
- how-to-implement-equals-and-hashcode-using-the-jpa-entity-identifier
- hibernate-facts-equals-and-hashcode
package com.stackoverflow.SO34299054;
import static org.junit.Assert.*;
import java.util.Random;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import org.junit.Test;
import lombok.AccessLevel;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
@SuppressWarnings("javadoc")
public class Answer {
@Entity
@Builder(toBuilder = true)
@AllArgsConstructor(access = AccessLevel.PACKAGE)
@NoArgsConstructor(access = AccessLevel.PACKAGE)
@Setter(value = AccessLevel.PACKAGE)
@Getter
public static class Person {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
/*
* IMPORTANT:
* Set toString, equals, and hashCode as described in these
* documents:
* - https://vladmihalcea.com/the-best-way-to-implement-equals-hashcode-and-tostring-with-jpa-and-hibernate/
* - https://vladmihalcea.com/how-to-implement-equals-and-hashcode-using-the-jpa-entity-identifier/
* - https://vladmihalcea.com/hibernate-facts-equals-and-hashcode/
*/
}
/**
* Test person builder.
*/
@Test
public void testPersonBuilder() {
final Long expectedId = new Random().nextLong();
final Person fromBuilder = Person.builder()
.id(expectedId)
.build();
assertEquals(expectedId, fromBuilder.getId());
}
/**
* Test person constructor.
*/
@Test
public void testPersonConstructor() {
final Long expectedId = new Random().nextLong();
final Person fromNoArgConstructor = new Person();
fromNoArgConstructor.setId(expectedId);
assertEquals(expectedId, fromNoArgConstructor.getId());
}
}
Old Version using @Tolerate
and @Data
:
Using @Tolerate
worked to allow adding a noarg constructor.
Since you want to use the builder pattern I imagine you want to control visibility of the setter methods.
The @Data
annotation makes the generated setters public
, applying @Setter(value = AccessLevel.PROTECTED)
to the fields makes them protected
.
Remember to properly override toString
, equals
, and hashCode
.
See the following posts by Vlad Mihalcea for details:
- the-best-way-to-implement-equals-hashcode-and-tostring-with-jpa-and-hibernate
- how-to-implement-equals-and-hashcode-using-the-jpa-entity-identifier
- hibernate-facts-equals-and-hashcode
package lombok.javac.handlers.stackoverflow;
import static org.junit.Assert.*;
import java.util.Random;
import javax.persistence.GenerationType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import lombok.AccessLevel;
import lombok.Builder;
import lombok.Data;
import lombok.Setter;
import lombok.experimental.Tolerate;
import org.junit.Test;
public class So34241718 {
@Builder
@Data
public static class Person {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Setter(value = AccessLevel.PROTECTED)
Long id;
@Tolerate
Person() {}
/* IMPORTANT:
Override toString, equals, and hashCode as described in these
documents:
- https://vladmihalcea.com/the-best-way-to-implement-equals-hashcode-and-tostring-with-jpa-and-hibernate/
- https://vladmihalcea.com/how-to-implement-equals-and-hashcode-using-the-jpa-entity-identifier/
- https://vladmihalcea.com/hibernate-facts-equals-and-hashcode/
*/
}
@Test
public void testPersonBuilder() {
Long expectedId = new Random().nextLong();
final Person fromBuilder = Person.builder()
.id(expectedId)
.build();
assertEquals(expectedId, fromBuilder.getId());
}
@Test
public void testPersonConstructor() {
Long expectedId = new Random().nextLong();
final Person fromNoArgConstructor = new Person();
fromNoArgConstructor .setId(expectedId);
assertEquals(expectedId, fromNoArgConstructor.getId());
}
}