@Autowired, @Resource, and @Inject are examples for annotations that are used for dependency injection in Spring.

While @Autowired is provided by the Spring framework, @Resource and @Inject are java standard annotations.

When using annotation-based dependency injection, if the dependency is not injected, we would get an exception at the startup of our application itself.

test

A composite key is a primary key composed of multiple columns.

When you are creating a composite key, your persistent class must override the equals() and hashCode() method. This is required for for Hibernate caching to work correctly. It must also implement the Serializable interface.

Best way to do this is to create a class with all your composite key fields, mark it as @Embeddable and then annotate a field of that class type with @Id in your entity class.

@Embeddable

An entity is a type on its own and has an existence of its own (e.g. Course, User etc.).

A value type is a type which doesn't have existence of its own, but belongs to an entity (e.g. Address of an User). Value types are always completely owned by their containing entity.

Defining entities and value types in Hibernate

You have different logging options in Hibernate and let us see some of those options quickly. Hibernate supports simple property based log enabling to supporting standard logging frameworks and even programmatically accessing log statistics.