Could not instantiate persister org.hibernate.persister.entity.SingleTableEntityPersister ----------------------------------------------------------------------------------------- Key: HHH-7196 URL: https://hibernate.onjira.com/browse/HHH-7196 Project: Hibernate ORM Issue Type: Bug Components: core Affects Versions: 4.1.1 Environment: 4.1.1, Windows XP, In Memory HSQLDB 2.2.8 Reporter: stanislav bashkirtsev Labels: exception While mapping the OTO, I've an NPE. I'm not strong in annotations and it's possible that the mapping is wrong, but anyway I'd assume that the exception should be more explanatory: {code}23-Mar-2012 14:40:16 org.hibernate.annotations.common.Version <clinit> INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final} 23-Mar-2012 14:40:16 org.hibernate.Version logVersion INFO: HHH000412: Hibernate Core {4.1.1} 23-Mar-2012 14:40:16 org.hibernate.cfg.Environment <clinit> INFO: HHH000206: hibernate.properties not found 23-Mar-2012 14:40:16 org.hibernate.cfg.Environment buildBytecodeProvider INFO: HHH000021: Bytecode provider name : javassist 23-Mar-2012 14:40:16 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure INFO: HHH000402: Using Hibernate built-in connection pool (not for production use!) 23-Mar-2012 14:40:16 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure INFO: HHH000115: Hibernate connection pool size: 20 23-Mar-2012 14:40:16 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure INFO: HHH000006: Autocommit mode: false 23-Mar-2012 14:40:16 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure INFO: HHH000401: using driver [org.hsqldb.jdbcDriver] at URL [jdbc:hsqldb:mem:testdb] 23-Mar-2012 14:40:16 org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure INFO: HHH000046: Connection properties: {user=sa, password=****} 23-Mar-2012 14:40:16 org.hibernate.dialect.Dialect <init> INFO: HHH000400: Using dialect: org.hibernate.dialect.HSQLDialect 23-Mar-2012 14:40:16 org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService INFO: HHH000399: Using default transaction strategy (direct JDBC transactions) 23-Mar-2012 14:40:16 org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init> INFO: HHH000397: Using ASTQueryTranslatorFactory Exception in thread "main" org.hibernate.MappingException: Could not instantiate persister org.hibernate.persister.entity.SingleTableEntityPersister at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:174) at org.hibernate.persister.internal.PersisterFactoryImpl.createEntityPersister(PersisterFactoryImpl.java:148) at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:820) at org.hibernate.metamodel.source.internal.SessionFactoryBuilderImpl.buildSessionFactory(SessionFactoryBuilderImpl.java:65) at org.hibernate.metamodel.source.internal.MetadataImpl.buildSessionFactory(MetadataImpl.java:340) at poc.hibernate.Main.main(Main.java:37) Caused by: java.lang.NullPointerException at org.hibernate.tuple.PropertyFactory.buildStandardProperty(PropertyFactory.java:288) at org.hibernate.tuple.entity.EntityMetamodel.<init>(EntityMetamodel.java:442) at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:791) at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:460) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at org.hibernate.persister.internal.PersisterFactoryImpl.create(PersisterFactoryImpl.java:163){code} Test Case: {code}@Entity @Table(name = "AUTHOR") public class Author { @Id @GeneratedValue private Long id; public Long getId() { return id; } public void setId(Long id) { this.id = id; } }{code} The original exceptions is thrown in _PropertyFactory_ on the line 288 when it appears that type variable is _null_. {code}@Entity @Table(name = "BOOK") public class Book { @Id @GeneratedValue private Long id; @OneToOne private Author author; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public Author getAuthor() { return author; } public void setAuthor(Author author) { this.author = author; } }{code} {code}public class Main { public static void main(String[] args) { Configuration configuration = new Configuration() .setProperty("hibernate.archive.autodetection", "class") .setProperty("hibernate.connection.driver_class", "org.hsqldb.jdbcDriver") .setProperty("hibernate.dialect", "org.hibernate.dialect.HSQLDialect") .setProperty("hibernate.hbm2ddl.auto", "create") .setProperty("hibernate.connection.url", "jdbc:hsqldb:mem:testdb") .setProperty("hibernate.connection.username", "sa") .setProperty("hibernate.connection.password", "") .setProperty("connection.pool_size", "2"); ServiceRegistry serviceRegistry = new ServiceRegistryBuilder() .applySettings(configuration.getProperties()) .buildServiceRegistry(); MetadataSources metadataSources = new MetadataSources(serviceRegistry); metadataSources .addAnnotatedClass(Author.class) .addAnnotatedClass(Book.class); SessionFactory sessionFactory = metadataSources.buildMetadata().buildSessionFactory(); } }{code}