The EntityManager API is great, but how does the server/ application know which database it is supposed to save / update / query the entity objects?
How do we configure the underlying object-relational-mapping engine and cache for better performance and trouble shooting? The persistence.xml file gives you complete flexibility to configure the EntityManager.
- The persistence.xml file is a standard configuration file in JPA.
- It has to be included in the META-INF directory inside the JAR file that contains the entity beans.
- The persistence.xml file must define a persistence-unit with a unique name in the current scoped classloader.
- The provider attribute specifies the underlying implementation of the JPA EntityManager.
- In JBoss AS, the default and only supported / recommended JPA provider is Hibernate.
- The jta-data-source points to the JNDI name of the database this persistence unit maps to e.g. java:/DefaultDS.
Thanks for your comment in my blog Sharad. you have good content and very good blog man. keep it up.
ReplyDeleteJavin
<a href="http://javarevisited.blogspot.com/2011/04/top-20-core-java-interview-questions.html>Top 20 Core Java Interview question</a>
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Deletehttp://thecafetechno.com/tutorials/interview-questions/most-frequently-asked-core-java-interview-questions-and-answers/