Springでビルドが失敗する

前提・実現したいこと

SpringとPostgreを連携させようとしたいのですが上手くいきません。
Postgreを入れてServiceやentityを作っている最中にビルドができなくなったので、連携時の何かが原因だと思いますが。。

発生している問題・エラーメッセージ

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-08-27 22:35:49.753 ERROR 5475 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'systemUserRepository' defined in com.example.demo.SystemUserRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Cannot resolve reference to bean 'jpaMappingContext' while setting bean property 'mappingContext'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.hibernate.AnnotationException: No identifier specified for entity: com.example.demo.SystemUser
	
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is org.hibernate.AnnotationException: No identifier specified for entity: com.example.demo.SystemUser

該当のソースコード

HelloController
package com.example.demo;

import java.util.List;

import javax.servlet.http.HttpSession;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class HelloController {

	@Autowired
	private SystemUserService userService;

	@RequestMapping(value = "/")
	private String index() {
		return "index";
	}

	@RequestMapping(value = "/form/edit")
	private String edit() {
		return "/form/edit";
	}

	@RequestMapping("/form/editCheck")
	public String editCheck(@ModelAttribute("form") Form form) {

		return "/form/editCheck";
	}

	@RequestMapping("/form/finish")
	public String finish(HttpSession session) {
		SystemUser sessionEditForm = (SystemUser) session.getAttribute("form");

		this.userService.save(sessionEditForm);

		return "/form/finish";
	}

	@RequestMapping(value = "/test", method = RequestMethod.GET)
	public List<SystemUser> test() {
		return userService.findAll();
	}

	@ModelAttribute
	Form setupForm() {
		return new Form();
	}

}

SystemUser
package com.example.demo;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Table;

import org.springframework.data.annotation.Id;


@Entity
@Table(name = "systemuser")
public class SystemUser {

	  @Id
	  @GeneratedValue(strategy=GenerationType.IDENTITY)
	  @Column
	  private int id;

	  @Column
	  private String name;

	  @Column
	  private int age;

	  public int getId() {
	    return id;
	  }
	  public void setId(int id) {
	    this.id = id;
	  }
	  public String getName() {
	    return name;
	  }
	  public void setName(String name) {
	    this.name = name;
	  }
	  public int getAge() {
	    return age;
	  }
	  public void setAge(int age) {
	    this.age = age;
	  }

}

SystemUserRepository
package com.example.demo;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface SystemUserRepository extends JpaRepository<SystemUser, Integer> {



}

SystemUserService
package com.example.demo;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
@Transactional
public class SystemUserService {

	@Autowired
	SystemUserRepository userRepositry;

	public SystemUser save(SystemUser entity) {

		return this.userRepositry.save(entity);
	}

	public List<SystemUser> findAll() {
		return userRepositry.findAll();
	}

}

apprication
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.url=jdbc:postgresql://localhost:5432/mydb
spring.datasource.username=username
spring.datasource.password=password

pom
<?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>2.3.3.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>demo</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</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>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
		<!-- データベースアクセス -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>
		<dependency>
			<groupId>org.postgresql</groupId>
			<artifactId>postgresql</artifactId>
			<scope>runtime</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>