JDO provides for the transparent persistence of data in a data store agnostic manner, supporting object, hierarchical, as well as relational stores. setFetchSize(int) defines the number of rows that will be read from the database when the ResultSet needs more rows. The method in the java.sql.Statement interface will set the 'default' value for all the ResultSet derived from that Statement; the method in the java.sql.ResultSet interface will override that value for a specific ResultSet.

JPA is a specification for persistence in Java EE and SE applications. As with all specifications they still require vendors or open source projects to implement them. TopLink Essentials is the first compliant JPA implementation providing the persistence functionality to the EJB 3.0 reference implementation. Oracle TopLink is Oracle's commercial implementationcurrently providing preview functionality of JPA. See similar questions...

The Enterprise JavaBeans (EJB) 3.0 specification includes an additional persistence specification called the Java Persistence API (JPA). It is an API for creating, removing and querying across lightweight Java objects and can be used both within a compliant EJB 3.0 Container and a standard Java SE 5 environment. See similar questions...

specified by JDO all persistent classe must implement the interface javax.jdo.spi.PersistenceCapable. If a class does not implement this interface a JDO implementation does not know how to handle it. On the other hand the JDO spec claims to provide transaparent persistence. That is no persistence class is required to implement a specific interface or to be derived from a special base class. See similar questions...

Castor JDO requires a reference to the actual collection to be returned from the get-method. By default the source generator does not provide such a method. To enable such methods to be created, simple add the following line to your castorbuilder.properties file: org.exolab.castor.builder.extraCollectionMethods=true See similar questions...

The Grails DomainBinder does not use the annotations, so you have to put the Domain class in the src/groovy folder (instead of grails-app/domain). import javax.persistence.*; @Entity class Book { @Id @GeneratedValue(strategy = GenerationType. See similar questions...

of AppFuse 2.0 M5+, it's as easy as changing your changing the <dao.framework> property in your root pom.xml to ibatis or jpa (jpa-hibernate in 2.0 M5). For further instructions, please see the JPA and iBATIS tutorials. See similar questions...

Migrating to JDO later will be smooth if you follow the following steps. I recommend to first divide your model layer into Activity- (or Process-) classes and Entity classes. Entity classes represent classes that must be made persistent at some point in time, say a "Customer" or a "Order" object. These persistent classes and the repsective O/R mapping in repository.xml will remain unchanged. Activities are classes that perform business tasks and work upon entities, e.g. See similar questions...