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Error: "javax.persistence.JoinColumn.foreignKey()Ljavax/persistence/ForeignKey" I was  trying to implement Hibernate Search functionality on my current project. I faced the above issue and resolved it with some research. Root cause and Solution:   JoinColumn.foreignKey() was introduced with JPA 2.1, which was not implemented by Hibernate 4 until version 4.3. If you're using an older version of Hibernate 4, you will face this issue. Try to upgrade it to hibernate-jpa-2.1-api   and also Hibernate to 4.3.x. If you're already using Hibernate 4.3 then make sure you're also using hibernate-jpa-2.1-api to make sure the API and implementation match up.

Error: “org.hibernate.ObjectNotFoundException: No row with the given identifier exists” but it does exists. I was facing this issue with my current project. There might be 2 possible reasons to occur this error. Root Causes: 1. Whene there is relationship between two tables in the database, the main entity may not exists in the database, You can check it with session.get() method whether it is there or not.

1. What is Hibernate? Hibernate is a powerful, high performance object/relational persistence and query service. This lets the users to develop persistent classes following object-oriented principles such as association, inheritance, polymorphism, composition, and collections. 2. What is ORM? ORM stands for Object/Relational mapping. It is the programmed and translucent perseverance of objects in a Java application in to the tables of a relational database using the metadata that describes the mapping between the objects and the database. It works by transforming the data from one representation to another.

The meta model is the model used by Hibernate core to perform its object relational mapping. The model includes information about tables, columns, classes, properties, components, values, collections etc. The API is in org.hibernate.mapping and its main entry point is the Configuration class, the same class that is used to build a session factory. The model represented by the Configuration class can be build in many ways. The following list the currently supported ones in Hibernate Tools. A Core configuration uses Hibernate Core and supports reading hbm.xml files, requires a hibernate.cfg.xml. Named core in Eclipse and <configuration> in ant.

Hibernate defines and supports the following object states. Transient - an object is transient if it has just been instantiated using the new operator, and it is not associated with a Hibernate Session. It has no persistent representation in the database and no identifier value has been assigned. Transient instances will be destroyed by the garbage collector if the application doesn't hold a reference anymore. Use the Hibernate Session to make an object persistent (and let Hibernate take care of the SQL statements that need to be executed for this transition. Persistent - a persistent instance has a representation in the database and an identifier value. It might just have been saved or loaded, however, it is by definition in the scope of a Session. Hibernate will detect any changes made to an object in persistent state and synchronize the state with the database when the unit of work completes. Developers don't execute manual UPDATE statements, or DELETE statements when...

Q. How will you configure Hibernate? Answer: The configuration files hibernate.cfg.xml (or hibernate.properties) and mapping files *.hbm.xml are used by the Configuration class to create (i.e. configure and bootstrap hibernate) the SessionFactory, which in turn creates the Session instances. Session instances are the primary interface for the persistence service. " hibernate.cfg.xml (alternatively can use hibernate.properties): These two files are used to configure the hibernate sevice (connection driver class, connection URL, connection username, connection password, dialect etc). If both files are present in the classpath then hibernate.cfg.xml file overrides the settings found in the hibernate.properties file. " Mapping files (*.hbm.xml): These files are used to map persistent objects to a relational database. It is the best practice to store each object in an individual mapping file (i.e mapping file per class) because storing large number of persistent classes ...