BeanCreationExceptionというエラーが出る[Spring Boot]

前提・実現したいこと

spring bootでMySQLに接続して、CRUD操作ができるようにしたいです。
@Entityを利用して、自動でテーブルが作れるようになりたいです。
実行すると以下のエラーメッセージが発生しました。

発生している問題・エラーメッセージ

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 org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.demo.model.Employee.department in com.example.demo.model.Department.employees
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.9.jar:5.3.9]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.9.jar:5.3.9]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.9.jar:5.3.9]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.5.4.jar:2.5.4]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) ~[spring-boot-2.5.4.jar:2.5.4]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434) ~[spring-boot-2.5.4.jar:2.5.4]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) ~[spring-boot-2.5.4.jar:2.5.4]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-2.5.4.jar:2.5.4]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332) ~[spring-boot-2.5.4.jar:2.5.4]
	at com.example.demo.DbCrudApplication.main(DbCrudApplication.java:10) ~[classes/:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.5.4.jar:2.5.4]
Caused by: org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.demo.model.Employee.department in com.example.demo.model.Department.employees
	at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:848) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:799) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:53) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1693) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1661) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:295) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255) ~[hibernate-core-5.4.32.Final.jar:5.4.32.Final]
	at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.9.jar:5.3.9]
	at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.9.jar:5.3.9]
	at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.9.jar:5.3.9]
	at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.9.jar:5.3.9]
	at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845) ~[spring-beans-5.3.9.jar:5.3.9]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782) ~[spring-beans-5.3.9.jar:5.3.9]
	... 21 common frames omitted

該当のソースコード

applicationProperties
1spring.jpa.hibernate.ddl-auto=update
2spring.datasource.url=jdbc:mysql://localhost:3306/spring_crud
3spring.datasource.username=root
4spring.datasource.password=system
5spring.datasource.driver-class-name =com.mysql.cj.jdbc.Driver
6spring.sql.init.encoding=utf-8
7spring.datasource.initialization-mode=always
8spring.jpa.database=MYSQL

試したこと

エラーでhibernateとでていたので、application.propertiesの「spring.jpa.hibernate.ddl-auto=」を、none,create,create-drop,と試しましたが同じ結果でした。
他のにも、application.propertiesの設定を追加したりしましたが、同じエラーでした。