Showing posts with label hibernate interview questions. Show all posts
Showing posts with label hibernate interview questions. Show all posts

Thursday, January 19, 2012

Java Interview Question and Java Beginner Tutorial - Part 12

What’s new in the EJB 2.0 specification?

Following are the main features supported in EJB 2.0: Integration of EJB with JMS, Message Driven Beans, Implement additional Business methods in Home interface which are not specific for bean instance, EJB QL.

    Java Interview Question and Java Beginner Tutorial - Part 8

    Is there a guarantee of uniqueness for entity beans?

    There is no such guarantee. The server (or servers) can instantiate as many instances of the same underlying Entity Bean (with the same PK) as it wants. However, each instance is guaranteed to have up-to-date data values, and be transactionally consistent, so uniqueness is not required. This allows the server to scale the system to support multiple threads, multiple concurrent requests, and multiple hosts.