Lombok #EqualsAndHashCode and Jhipster TestUtil.equalsVerifier - jhipster

Question

I am using Jhipster and Lombok for my Java project.
I removed the entity object equals() and hashcode() method generated by Jhipster and replaced with lombok #EqualsAndHashCode
Originally generated By Jhipster
#Entity
#Table(name = "category")
#Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class Category implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Size(max = 100)
#Column(name = "name", length = 100)
private String name;
// jhipster-needle-entity-add-field - JHipster will add fields here
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public Category name(String name) {
this.name = name;
return this;
}
public void setName(String name) {
this.name = name;
}
// jhipster-needle-entity-add-getters-setters - JHipster will add getters and setters here
#Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Category)) {
return false;
}
return id != null && id.equals(((Category) o).id);
}
#Override
public int hashCode() {
return 31;
}
// prettier-ignore
#Override
public String toString() {
return "Category{" +
"id=" + getId() +
", name='" + getName() + "'" +
"}";
}
}
Modified to use Lombok
#Entity
#Data
#EqualsAndHashCode(callSuper = true)
#Table(name = "category")
public class Category extends AbstractAuditingEntity implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Size(max = 100)
#Column(name = "name", length = 100)
private String name;
}
The problem is the test generated by Jhipster below fails. At the last 2 lines of the test
/**
* Verifies the equals/hashcode contract on the domain object.
*/
public static <T> void equalsVerifier(Class<T> clazz) throws Exception {
T domainObject1 = clazz.getConstructor().newInstance();
assertThat(domainObject1.toString()).isNotNull();
assertThat(domainObject1).isEqualTo(domainObject1);
assertThat(domainObject1.hashCode()).isEqualTo(domainObject1.hashCode());
// Test with an instance of another class
Object testOtherObject = new Object();
assertThat(domainObject1).isNotEqualTo(testOtherObject);
assertThat(domainObject1).isNotEqualTo(null);
// Test with an instance of the same class
T domainObject2 = clazz.getConstructor().newInstance();
assertThat(domainObject1).isNotEqualTo(domainObject2); //this fails
// HashCodes are equals because the objects are not persisted yet
assertThat(domainObject1.hashCode()).isEqualTo(domainObject2.hashCode()); //this also fails
}
May I know what is the purpose of the test?
every clazz.getConstructor().newInstance(); object should not be equal with each other? The content of the object is the same. Why not?
every clazz.getConstructor().newInstance(); object should have same hashCode? If so, why lombok #EqualsAndHashCode gives different hashcode?
How can I fix the problem?
*Note that the class extends AbstractAuditingEntity
#MappedSuperclass
#EntityListeners(AuditingEntityListener.class)
public abstract class AbstractAuditingEntity implements Serializable {
private static final long serialVersionUID = 1L;
#CreatedBy
#Column(name = "created_by", nullable = false, length = 50, updatable = false)
#JsonIgnore
private String createdBy;
#CreatedDate
#Column(name = "created_date", updatable = false)
#JsonIgnore
private Instant createdDate = Instant.now();
#LastModifiedBy
#Column(name = "last_modified_by", length = 50)
#JsonIgnore
private String lastModifiedBy;
#LastModifiedDate
#Column(name = "last_modified_date")
#JsonIgnore
private Instant lastModifiedDate = Instant.now();
public String getCreatedBy() {
return createdBy;
}
public void setCreatedBy(String createdBy) {
this.createdBy = createdBy;
}
public Instant getCreatedDate() {
return createdDate;
}
public void setCreatedDate(Instant createdDate) {
this.createdDate = createdDate;
}
public String getLastModifiedBy() {
return lastModifiedBy;
}
public void setLastModifiedBy(String lastModifiedBy) {
this.lastModifiedBy = lastModifiedBy;
}
public Instant getLastModifiedDate() {
return lastModifiedDate;
}
public void setLastModifiedDate(Instant lastModifiedDate) {
this.lastModifiedDate = lastModifiedDate;
}
}