Could not load requested class exception for a class implementing Spring Security UserDetails

medkhelifi :

I use a LocalContainerEntityManagerFactoryBean to setting up a JPA EntityManagerFactory. Among the scanned entities I scan with setPackagesToScan I have a User entity that implement spring security interface UserDetails.

When I lunch my application I have this error:

Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [com.medkhelifi.model.entities.User]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:354)
    at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.<init>(AnnotationMetadataSourceProcessorImpl.java:105)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.<init>(MetadataBuildingProcess.java:156)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:150)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:904)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935)
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1821)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1758)
    ... 11 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : com.medkhelifi.model.entities.User
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:342)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:351)
    ... 23 more

This is how I configured my application: **Beans config: **

@Configuration
@PropertySource("classpath:application.properties")
@ComponentScan("com.medkhrlifi.tutorials.designpatterns.dao")
@EnableTransactionManagement
public class AppConfig {
    // properties variable goes here ...    

    @Bean
    public DataSource dataSource(){
        // datasource config goes here ...
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean(){
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);

        LocalContainerEntityManagerFactoryBean lem = new LocalContainerEntityManagerFactoryBean();
        lem.setDataSource(dataSource());
        lem.setJpaVendorAdapter(vendorAdapter);
        lem.setPackagesToScan("com.medkhelifi.model.entities");
        lem.setJpaProperties(jpaProperties());
        //lem.afterPropertiesSet();
        return lem;
    }

    @Bean
    public PlatformTransactionManager platformTransactionManager(){
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
        return txManager;
    }

    @Bean
    public Properties jpaProperties(){
        Properties jpa = new Properties();
        jpa.put("hibernate.dialect", dialect);
        return jpa;
    }
}

User entity

@Data
@Entity
@Table(name = "user")
public class User implements UserDetails {
    private static final Logger logger = LoggerFactory.getLogger(User.class);

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private String id;

    @NotEmpty
    private String firstname;

    @NotEmpty
    private String lastname;

    @NotEmpty
    private String email;

    @NotEmpty
    private String password;


    //@ElementCollection(fetch = FetchType.EAGER)
    //@Builder.Default
    @DBRef
    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "user_role",
            joinColumns = @JoinColumn(name = "id_user"),
            inverseJoinColumns = @JoinColumn(name = "id_role"))
    private List<Role> roles = new ArrayList<>();

    // Override methods goes here
}

** UPDATE ** I know that the error came from the UserDetails interface implementation, because if I remove it my app start normally, but this is not what I want.

This is how I run my app (for test purpose only):

public class DaoApp {

    private static AnnotationConfigApplicationContext applicationContext=  new AnnotationConfigApplicationContext (AppConfig.class);

    public static void main(String[] args) throws ParseException {
        System.out.println("main app for test purpose only started successfully");  
    }
}

I hope I have provided enough information to be helped.

medkhelifi :

I bypassed the problem by removing the implementation of the UserDetails interface from my User entity, and set up a new mechanism to recover the GrantedAuthority necessary for Spring Security. But I still do not understand why this interface implementation poses a problem with setPackagesToScan used by the JPA EntityManagerFactory.

If somone can give us an explanation?