Creating a OneToMany relationship between two objects in Spring Boot Kotlin

Question

I'm struggling to wrap my head around how relationships are supposed to be set out in Spring Boot.

At the moment I have a User class (unfortunately in Java as I've not gotten around to converting it to Kotlin) and a Job class (in Kotlin).

When a Job is created, I need the user to be assigned to it. I also want to be able to see who created the job from Job.

Here's what I've tried so far:

User.java

@OneToMany(mappedBy="creationUser")
private Set<Job> createdJobs = new HashSet<>()

...

public Set<Job> getCreatedJobs() { return createdJobs; }

public void setCreatedJobs(Set<Job> createdJobs) { this.createdJobs = createdJobs; }

Job (Kotlin data class):

@Column(name = "creationUser")
val creationUser: User? = null,

I get the following error when I try and run it (still a little new to Spring Boot so not sure what it's saying)

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not determine type for: com.jre.hireout.database.entities.users.User, at table: table_jobs, for columns: [org.hibernate.mapping.Column(creation_user)]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1804) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.22.jar:5.3.22]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.22.jar:5.3.22]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.22.jar:5.3.22]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.3.jar:2.7.3]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.3.jar:2.7.3]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.3.jar:2.7.3]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.3.jar:2.7.3]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.3.jar:2.7.3]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.3.jar:2.7.3]
    at com.jre.hireout.HireOutApplication.main(HireOutApplication.java:26) ~[classes/:na]
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:577) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.7.3.jar:2.7.3]
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not determine type for: com.jre.hireout.database.entities.users.User, at table: table_jobs, for columns: [org.hibernate.mapping.Column(creation_user)]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:421) ~[spring-orm-5.3.22.jar:5.3.22]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.22.jar:5.3.22]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) ~[spring-beans-5.3.22.jar:5.3.22]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.3.22.jar:5.3.22]
    ... 19 common frames omitted
Caused by: org.hibernate.MappingException: Could not determine type for: com.jre.hireout.database.entities.users.User, at table: table_jobs, for columns: [org.hibernate.mapping.Column(creation_user)]
    at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:515) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:482) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.mapping.Property.isValid(Property.java:231) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:627) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.mapping.RootClass.validate(RootClass.java:267) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:359) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:314) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:471) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1498) ~[hibernate-core-5.6.10.Final.jar:5.6.10.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.22.jar:5.3.22]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.22.jar:5.3.22]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.22.jar:5.3.22]
    ... 23 common frames omitted

Answer 1

The way you are declaring this, you are telling Hibernate that creationUser is a basic typed field, where basic types are things like String , Integer etc.

You should instead mark this as an association and use the @JoinColumn annotation.

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "creationUser")
val creationUser: User? = null,