Why pojo in hibernate

Disabling proxies in hbm. If the final class does implement a proper interface, you could alternatively tell Hibernate to use the interface instead when generating the proxies. Proxying an interface in hbm.

You should also avoid declaring public final methods as this will again limit the ability to generate proxies from this class. If you want to use a class with public final methods, you must explicitly disable proxying.

Again, see Example 4. Cat declares accessor methods for all its persistent fields. Many other ORM tools directly persist instance variables. It is better to provide an indirection between the relational schema and internal data structures of the class. By default, Hibernate persists JavaBeans style properties and recognizes method names of the form getFoo , isFoo and setFoo.

If required, you can switch to direct field access for particular properties. Properties need not be declared public. Hibernate can persist a property declared with package , protected or private visibility as well. A subclass must also observe the first and second rules. It inherits its identifier property from the superclass, Cat. For example:. You have to override the equals and hashCode methods if you:. Hibernate guarantees equivalence of persistent identity database row and Java identity only inside a particular session scope.

When you mix instances retrieved in different sessions, you must implement equals and hashCode if you wish to have meaningful semantics for Set s.

If the value is the same, both must be the same database row, because they are equal. If both are added to a Set , you will only have one element in the Set. Unfortunately, you cannot use that approach with generated identifiers.

Hibernate will only assign identifier values to objects that are persistent; a newly created instance will not have any identifier value. Furthermore, if an instance is unsaved and currently in a Set , saving it will assign an identifier value to the object. If equals and hashCode are based on the identifier value, the hash code would change, breaking the contract of the Set. See the Hibernate website for a full discussion of this problem.

This is not a Hibernate issue, but normal Java semantics of object identity and equality. It is recommended that you implement equals and hashCode using Business key equality.

Business key equality means that the equals method compares only the properties that form the business key. It is a key that would identify our instance in the real world a natural candidate key :.

A business key does not have to be as solid as a database primary key candidate see Section If the created hibernate configuration is not listed, press the Refresh or Rebuild configuration button in the top right corner of the pane. The generated Hibernate configuration should look like the following figure.

We could expand the Database element on the Hibernate configuration to ensure we have a valid database connection. To run Hibernate code generation, ensure we select the active Hibernate Configuration in the Hibernate configuration pane. In the Hibernate Code Generation Configuration , fill the package where the domain class will be in. In the exporter list option, we can select items in the list that we need. In this post we only select Domain code that has annotation as Hibernate mapping.

Finally click Apply and Run to generate the domain code. If the annotation does not generated in the domain class, open the Hibernate Configuration and edit it. Then change the Hibernate Version to 5. POJO Plain Old Java Object is a programming model that follow some simple rules not required to follow these rules hardly to create a classes that implements the entities of the business problem.

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