Java Interview Questions » EJB Tutorial http://www.bestjavainterviewquestions.com Java Interview Questions | Core Java Interview Questions | Advanced Java Interview Questions | EJB Interview Questions | J2EE Interview Questions | Hibernate Interview Questions Fri, 30 Jul 2010 06:00:25 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 Define Stored Procedures http://www.bestjavainterviewquestions.com/define-stored-procedures/ http://www.bestjavainterviewquestions.com/define-stored-procedures/#comments Sun, 24 Aug 2008 13:34:01 +0000 Ramakrishna http://www.bestjavainterviewquestions.com/?p=191 Q) What are stored procedures? How is it useful?
A) A STORED PROCEDURES is a set of statements/commands which reside in the database. The stored procedure is pre-compiled and saves the database the effort of parsing and compiling sql statements every time a query is run.

Each database has its own stored procedure language, usually a variant of C with a SQL preproceesor. Newer versions of DB’s support writing stored procedures in Java and Perl too. Before the advent of 3-tier/n-tier architecture it was pretty common for stored procs to implement the business logic( A lot of systems still do it). The biggest advantage is of course speed.

Also certain kind of data manipulations are not achieved in SQL. Stored procs provide a mechanism to do these manipulations. Stored procs are also useful when you want to do Batch updates/exports/houseKeeping kind of stuff on the db. The overhead of a JDBC Connection may be significant in these cases.

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]]> http://www.bestjavainterviewquestions.com/define-stored-procedures/feed/ 0 Why does EJB needs two interfaces http://www.bestjavainterviewquestions.com/why-does-ejb-needs-two-interfaces/ http://www.bestjavainterviewquestions.com/why-does-ejb-needs-two-interfaces/#comments Sun, 24 Aug 2008 13:27:56 +0000 Ramakrishna http://www.bestjavainterviewquestions.com/?p=186 Q) Why does EJB needs two interfaces(Home and Remote Interface)
A) There is a pure division of roles between the two .
Home Interface is the way to communicate with the container which is responsible for creating , locating and removing beans and Remote Interface is the link to the bean that allows acces to all methods and members.

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]]> http://www.bestjavainterviewquestions.com/why-does-ejb-needs-two-interfaces/feed/ 0 How many EJB Objects are created for a Bean http://www.bestjavainterviewquestions.com/how-many-ejb-objects-are-created-for-a-bean/ http://www.bestjavainterviewquestions.com/how-many-ejb-objects-are-created-for-a-bean/#comments Sun, 24 Aug 2008 13:25:27 +0000 Ramakrishna http://www.bestjavainterviewquestions.com/?p=183 Q) How many EJB Objects are created for a Bean?
A) For a Session bean – one EJB object for one bean instance.
For entity bean – it depends , if 2 users are accessing one row at a time then one EJB object is used for both the beans other wise for each bean one EJB object.

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]]> http://www.bestjavainterviewquestions.com/how-many-ejb-objects-are-created-for-a-bean/feed/ 0 Software Architecture of EJB http://www.bestjavainterviewquestions.com/software-architecture-of-ejb/ http://www.bestjavainterviewquestions.com/software-architecture-of-ejb/#comments Sun, 24 Aug 2008 13:10:21 +0000 Ramakrishna http://www.bestjavainterviewquestions.com/?p=178 Q) What is software architecture of EJB?
A) Session and Entity EJBs consist of 4 and 5 parts respetively:

1. A remote interface (a client interacts with it),
2. A home interface (used for creating objects and for declaring business methods),
3. A bean object (an object, which actually performs business logic and EJB-specific operations).
4. A deployment descriptor (an XML file containing all information required for maintaining the EJB) or a set of deployment descriptors (if you are using some container-specific features).
5.A Primary Key class – is only Entity bean specific.

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