Error creating bean with name 'entityManagerFactory' error in a Spring boot web application - spring

Question

I'm a beginner in Spring boot coding
When I run my spring boot web application, I got the following error.
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 java.lang.ClassCastException: org.hibernate.mapping.SingleTableSubclass cannot be cast to org.hibernate.mapping.RootClass
I am using STS Eclipse and MySql Database
My Connection string in Application.Properties is
spring.datasource.url=jdbc:mysql://localhost:3306/dreamhospital?zeroDateTimeBehavior=CONVERT_TO_NULL&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
spring.main.banner-mode=off
server.port=8100
and this is my pom.xml :
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.DreamHospital</groupId>
<artifactId>DreamHospital</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>DreamHospital</name>
<description>Demo project for Spring Boot</description>
<properties>
<maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web-services</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-core</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.12</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>6.0.16.Final</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
here's my entities class:
this is patient entity:
#AllArgsConstructor
#NoArgsConstructor
#Getter
#Setter
#Entity
#DiscriminatorValue("patient")
public class patient implements Serializable{
#Id
private int id;
private String nom;
private String prenom;
#ManyToOne
#JoinColumn(name="idLit")
lit lit;
#ManyToOne
#JoinColumn(name="idM")
medecin medecin;
}
and this is User entity:
#Entity
#Inheritance(strategy=InheritanceType.SINGLE_TABLE)
#DiscriminatorColumn(name="fonction" , discriminatorType=DiscriminatorType.STRING,length=10)
public class User implements Serializable {
#Id
private String UserName;
private String Password;
#Column(name="fonction", insertable = false, updatable = false)
protected String fonction;
and this is medecin entity:
#Data
#Entity
#DiscriminatorValue("medecin")
public class medecin extends User implements Serializable {
#Id #GeneratedValue
private UUID idM;
private String nom;
private String specialite;
#OneToMany(mappedBy="idM")
List<patient> patients;
}
I tried many solutions proposed in stackoverflow but it didn't worked

Answer 1

Apparently there's problem with mappings of User and medecin, you cannot have #Id in superclass and another #Id in subclass. Removing #Id from idM in subclass (medecin) should prevent the exception.