MappingException: Entity Class Not Found

Hibernate ORM
1

As the title suggests, I’m getting an incredibly generic error message and I’m not entirely sure what is causing it. I’m currently using the core and hikaricp modules from the documentation. I’m also using the latest version

Here is my current pom.xml dependencies

<dependency>
    <groupId>org.hibernate.orm</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>6.4.4.Final</version>
    <scope>provided</scope>
</dependency>

<dependency>
    <groupId>org.hibernate.orm</groupId>
    <artifactId>hibernate-hikaricp</artifactId>
    <version>6.4.4.Final</version>
    <scope>provided</scope>
</dependency>

The class in question is properly annotated with @Entity and it’s respective properties.

@Entity
@Table(name = "seasons")
public class HSeason {.. // Stripped down to just an @Id

The way that I’m constructing this in-code is instead of using hibernate.cfg.xml I opted to use Properties class because I’ll be dealing with dynamically changing data. Here is my “Attempt” at initializing a session factory.

private void initSessionFactory() {
Properties properties = new Properties();

    MySQLConfig mySQLConfig = configManager.config.mySQLConfig;

    properties.putAll(Map.of(
            "hibernate.connection.provider_class", "org.hibernate.hikaricp.internal.HikariCPConnectionProvider",
            "hibernate.hikari.minimumIdle", "5",
            "hibernate.hikari.maximumPoolSize", "10",
            "hibernate.hikari.idleTimeout", "30000",
            "hibernate.hikari.dataSourceClassName", "com.mysql.cj.jdbc.MysqlDataSource",
            "hibernate.hikari.dataSource.url", "jdbc:mysql://" + mySQLConfig.host + ":" + mySQLConfig.port + "/" + mySQLConfig.database,
            "hibernate.hikari.dataSource.user", mySQLConfig.username,
            "hibernate.hikari.dataSource.password", mySQLConfig.password
    ));

    Configuration configuration = new Configuration();
    configuration.setProperties(properties);
    configuration.addPackage("us.mkaulfers.hardcoreseasons.orm");

    try {
        StandardServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                .applySettings(configuration.getProperties())
                .build();

        sessionFactory =
                new MetadataSources(serviceRegistry)
                        .addPackage(us.mkaulfers.hardcoreseasons.orm.HSeason.class.getPackageName())
                        .addAnnotatedClass(HSeason.class)
                        .buildMetadata()
                        .buildSessionFactory();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Every attempt I’ve made thus-far has resulted in the same error.

[21:23:42 WARN]: org.hibernate.MappingException: entity class not found: us.mkaulfers.hardcoreseasons.orm.HSeason
[21:23:42 WARN]: 	at org.hibernate.mapping.PersistentClass.getMappedClass(PersistentClass.java:171)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.BinderHelper.getPropertyOverriddenByMapperOrMapsId(BinderHelper.java:887)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.PropertyBinder.bindBasic(PropertyBinder.java:1016)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.PropertyBinder.bindProperty(PropertyBinder.java:890)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.PropertyBinder.buildProperty(PropertyBinder.java:788)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.PropertyBinder.processElementAnnotations(PropertyBinder.java:709)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.EntityBinder.processIdPropertiesIfNotAlready(EntityBinder.java:1041)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.EntityBinder.handleIdentifier(EntityBinder.java:357)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.EntityBinder.bindEntityClass(EntityBinder.java:237)
[21:23:42 WARN]: 	at org.hibernate.boot.model.internal.AnnotationBinder.bindClass(AnnotationBinder.java:423)
[21:23:42 WARN]: 	at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.processEntityHierarchies(AnnotationMetadataSourceProcessorImpl.java:256)
[21:23:42 WARN]: 	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:279)
[21:23:42 WARN]: 	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:322)
[21:23:42 WARN]: 	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:129)
[21:23:42 WARN]: 	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:449)
[21:23:42 WARN]: 	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:101)
[21:23:42 WARN]: 	at org.hibernate.boot.MetadataSources.buildMetadata(MetadataSources.java:210)
[21:23:42 WARN]: 	at HardcoreSeasons-1.1.0b.jar//us.mkaulfers.hardcoreseasons.HardcoreSeasons.initSessionFactory(HardcoreSeasons.java:121)
[21:23:42 WARN]: 	at HardcoreSeasons-1.1.0b.jar//us.mkaulfers.hardcoreseasons.HardcoreSeasons.onEnable(HardcoreSeasons.java:47)
[21:23:42 WARN]: 	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:287)
[21:23:42 WARN]: 	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:188)
[21:23:42 WARN]: 	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:104)
[21:23:42 WARN]: 	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:507)
[21:23:42 WARN]: 	at org.bukkit.craftbukkit.v1_20_R3.CraftServer.enablePlugin(CraftServer.java:639)
[21:23:42 WARN]: 	at org.bukkit.craftbukkit.v1_20_R3.CraftServer.enablePlugins(CraftServer.java:550)
[21:23:42 WARN]: 	at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:671)
[21:23:42 WARN]: 	at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:431)
[21:23:42 WARN]: 	at net.minecraft.server.dedicated.DedicatedServer.e(DedicatedServer.java:309)
[21:23:42 WARN]: 	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:1131)
[21:23:42 WARN]: 	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319)
[21:23:42 WARN]: 	at java.base/java.lang.Thread.run(Thread.java:840)
[21:23:42 WARN]: Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [us.mkaulfers.hardcoreseasons.orm.HSeason]
[21:23:42 WARN]: 	at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:126)
[21:23:42 WARN]: 	at org.hibernate.boot.internal.ClassLoaderAccessImpl.classForName(ClassLoaderAccessImpl.java:67)
[21:23:42 WARN]: 	at org.hibernate.mapping.PersistentClass.getMappedClass(PersistentClass.java:166)
[21:23:42 WARN]: 	... 30 more
[21:23:42 WARN]: Caused by: java.lang.ClassNotFoundException: Could not load requested class : us.mkaulfers.hardcoreseasons.orm.HSeason
[21:23:42 WARN]: 	at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:216)
[21:23:42 WARN]: 	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:592)
[21:23:42 WARN]: 	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525)
[21:23:42 WARN]: 	at java.base/java.lang.Class.forName0(Native Method)
[21:23:42 WARN]: 	at java.base/java.lang.Class.forName(Class.java:467)
[21:23:42 WARN]: 	at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:123)
[21:23:42 WARN]: 	... 32 more
[21:23:42 WARN]: Caused by: java.lang.Throwable
[21:23:42 WARN]: 	at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:209)
[21:23:42 WARN]: 	... 37 more
[21:23:42 WARN]: 	Suppressed: java.lang.ClassNotFoundException: us.mkaulfers.hardcoreseasons.orm.HSeason
[21:23:42 WARN]: 		at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
[21:23:42 WARN]: 		at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:592)
[21:23:42 WARN]: 		at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525)
[21:23:42 WARN]: 		at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:206)
[21:23:42 WARN]: 		... 37 more
[21:23:42 WARN]: 	Suppressed: java.lang.ClassNotFoundException: us.mkaulfers.hardcoreseasons.orm.HSeason
[21:23:42 WARN]: 		at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
[21:23:42 WARN]: 		at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:592)
[21:23:42 WARN]: 		at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525)
[21:23:42 WARN]: 		at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:206)
[21:23:42 WARN]: 		... 37 more
[21:23:42 WARN]: 	Suppressed: java.lang.ClassNotFoundException: us.mkaulfers.hardcoreseasons.orm.HSeason
[21:23:42 WARN]: 		at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
[21:23:42 WARN]: 		at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
[21:23:42 WARN]: 		at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525)
[21:23:42 WARN]: 		at org.hibernate.boot.registry.classloading.internal.AggregatedClassLoader.findClass(AggregatedClassLoader.java:206)
[21:23:42 WARN]: 		... 37 more
2

Looks like a class loading problem. I don’t know anything about the class loader structure of Minecraft plugins, but I guess that the thread context class loader might not have access to classes of the plugin and that the hibernate-core JAR file might be loaded by an isolated class loader.
You might have to ask Minecraft developers to understand this better. AFAIU, the plugin documentation suggests you might have to declare dependencies.

3

Maybe this documentation can help you further: Paper Plugins | PaperMC Documentation

4

I think you’re right. I adjusted the dependency to be compiled and the error went away. I’ll post back here after I work around it a bit. I searched far and wide for a solution on this initially so I suspect I’m not the only one haha.