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Spring Hibernate – Could not obtain transaction-synchronized Session for current thread

You must enable the transaction support (<tx:annotation-driven> or @EnableTransactionManagement) and declare the transactionManager and it should work through the SessionFactory. You must add @Transactional into your @Repository With @Transactional in your @Repository Spring is able to apply transactional support into your repository. Your Student class has no the @javax.persistence.* annotations how @Entity, I am assuming … Read more

Hibernate show real SQL

log4j.properties hibernate.cfg.xml persistence.xml Some frameworks use persistence.xml:

How to map a composite key with JPA and Hibernate?

To map a composite key, you can use the EmbeddedId or the IdClass annotations. I know this question is not strictly about JPA but the rules defined by the specification also applies. So here they are: 2.1.4 Primary Keys and Entity Identity … A composite primary key must correspond to either a single persistent field or property or to a … Read more

What’s the difference between JPA and Hibernate?

I understand that JPA 2 is a specification and Hibernate is a tool for ORM. Also, I understand that Hibernate has more features than JPA 2. But from a practical point of view, what really is the difference? I have experience using iBatis and now I’m trying to learn either Hibernate or JPA2. I picked … Read more

Hibernate – Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1

Without code and mappings for your transactions, it’ll be next to impossible to investigate the problem. However, to get a better handle as to what causes the problem, try the following: In your hibernate configuration, set hibernate.show_sql to true. This should show you the SQL that is executed and causes the problem. Set the log … Read more

What kind of Java type is “[B”?

That my friend is an array of bytes. In JNI, [B is used to describe an array ([) of bytes (B). An array of ints is [I etc. You can get a bit more information on field descriptors here:JNI Types and Data Structures (Table 3-2 should be what you are looking for).

Hibernate dialect for Oracle Database 11g?

Use the Oracle 10g dialect. Also Hibernate 3.3.2+ is required for recent JDBC drivers (the internal class structure changed – symptoms will be whining about an abstract class). Dialect of Oracle 11g is same as Oracle 10g (org.hibernate.dialect.Oracle10gDialect). Source: http://docs.jboss.org/hibernate/orm/3.6/reference/en-US/html/session-configuration.html#configuration-optional-dialects

SQL Error: 0, SQLState: 08S01 Communications link failure

The communication link between the driver and the data source to which the driver was attempting to connect failed before the function completed processing. So usually its a network error. This could be caused by packet drops or badly configured Firewall/Switch.

Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

You are missing a field annotated with @Id. Each @Entity needs an @Id – this is the primary key in the database. If you don’t want your entity to be persisted in a separate table, but rather be a part of other entities, you can use @Embeddable instead of @Entity. If you want simply a … Read more

Hibernate problem – “Use of @OneToMany or @ManyToMany targeting an unmapped class”

Your annotations look fine. Here are the things to check: make sure the annotation is javax.persistence.Entity, and not org.hibernate.annotations.Entity. The former makes the entity detectable. The latter is just an addition. if you are manually listing your entities (in persistence.xml, in hibernate.cfg.xml, or when configuring your session factory), then make sure you have also listed the ScopeTopic entity make … Read more

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