For the latest stable version, please use Spring Data Commons 3.4.1!

Entity State Detection Strategies

The following table describes the strategies that Spring Data offers for detecting whether an entity is new:

Table 1. Options for detection whether an entity is new in Spring Data
`@Id`-Property inspection (the default)	By default, Spring Data inspects the identifier property of the given entity. If the identifier property is `null` or `0` in case of primitive types, then the entity is assumed to be new. Otherwise, it is assumed to not be new.
`@Version`-Property inspection	If a property annotated with `@Version` is present and `null`, or in case of a version property of primitive type `0` the entity is considered new. If the version property is present but has a different value, the entity is considered to not be new. If no version property is present Spring Data falls back to inspection of the identifier property.
Implementing `Persistable`	If an entity implements `Persistable`, Spring Data delegates the new detection to the `isNew(…)` method of the entity. See the Javadoc for details. Note: Properties of `Persistable` will get detected and persisted if you use `AccessType.PROPERTY`. To avoid that, use `@Transient`.
Providing a custom `EntityInformation` implementation	You can customize the `EntityInformation` abstraction used in the repository base implementation by creating a subclass of the module specific repository factory and overriding the `getEntityInformation(…)` method. You then have to register the custom implementation of module specific repository factory as a Spring bean. Note that this should rarely be necessary.