J2EE

Advantages of using entity beans Types – Container and bean managed entity beans. It represents data from the database.

EJB invocation Client < EJB object <- RetrieveHome object -> Naming service -> JNDI

HTTP session sharing between JSP and EJB We can pass the fat session values between JSP and EJB, but not efficient. It is better to form value object as an abstraction layer where data can be modified and passes back and forth.

Primary key cannot be primitive datatype

Message driven bean VS Stateless Session bean MDB’s process multiple JMS messages simultaneously – stateless session bean process messages serially one by one. MDB’s are maintained by containers through whole lifecycle – Client requests or other API calls may invoke a stateless session bean

JNDI can be used to call one EJB inside other EJB

Only inner class can be declared as private

Deployment Descriptor in J2EE .ear File must in called in web.xml in WEB-INF directory and application.xml in MET-INF directory.

ANT VS Maven ANT is procedural where we need to define each and every step - Maven has a lifecycle it automatically created Jar when we configure POM.XML with source code