Interview Tutorials

11. What is Deployment Descriptor?

By: Karthik : 2012-06-16

Description: Answer: A deployment descriptor is simply an XML(Extensible Markup Language) file with the extension of .xml. Deployment descriptor describes the component deployment settings. Application servers reads the deployment descriptor to deploy the components contained in the deployment unit. For example ejb-jar.xml file is used to describe the setting of the EJBs.


12. What do you understand by JTA and JTS?

By: Karthik : 2012-06-16

Description: Answer: JTA stands for Java Transaction API and JTS stands for Java Transaction Service. JTA provides a standard interface which allows the developers to demarcate transactions in a manner that is independent of the transaction manager implementation.


13. What is JAXP?

By: Karthik : 2012-06-16

Description: Answer: The Java API for XML Processing (JAXP) enables applications to parse and transform XML documents independent of a particular XML processing implementation. JAXP or Java API for XML Parsing is an optional API provided by Javasoft. It provides basic functionality for reading, manipulating, and generating XML documents through pure Java APIs. It is a thin and lightweight API that provides a standard way to seamlessly integrate any XML-compliant parser with a Java application.


14. What is J2EE Connector architecture?

By: Karthik : 2012-06-16

Description: Answer: J2EE Connector Architecture (JCA) is a Java-based technology solution for connecting application servers and enterprise information systems (EIS) as part of enterprise application integration (EAI) solutions. While JDBC is specifically used to connect Java EE applications to databases, JCA is a more generic architecture for connection to legacy systems (including databases).


15. What is difference between Java Bean and Enterprise Java Bean?

By: Karthik : 2012-06-16

Description: Answer: Java Bean as is a plain java class with member variables and getter setter methods. Java Beans are defined under JavaBeans specification as Java-Based software component model which includes the features like introspection, customization, events, properties and persistence.


16. What is the difference between JTS and JTA?

By: Karthik : 2012-06-16

Description: Answer: In any J2EE application transaction management is one of the most crucial requirements of the application. Given the complexity of today's business requirements, transaction processing occupies one of the most complex segments of enterprise level distributed applications to build, deploy and maintain.


17. Can Entity Beans have no create() methods?

By: Karthik : 2012-06-16

Description: Answer: Entity Beans can have no create() methods. Entity Beans have no create() method, when entity bean is not used to store the data in the database. In this case entity bean is used to retrieve the data from database


18. What are the call back methods in Session bean?

By: Karthik : 2012-06-16

Description: Answer: Callback methods are called by the container to notify the important events to the beans in its life cycle. The callback methods are defined in the javax.ejb.EntityBean interface.The callback methods example are ejbCreate(), ejbPassivate(), and ejbActivate().


19. What is bean managed transaction?

By: Karthik : 2012-06-16

Description: Answer: In EJB transactions can be maintained by the container or developer can write own code to maintain the transaction. If a developer doesn’t want a Container to manage transactions, developer can write own code to maintain the database transaction.


20. What is transient variable?

By: Karthik : 2012-06-16

Description: Answer: Transient variable can't be serialize. For example if a variable is declared as transient in a Serializable class and the class is written to an ObjectStream, the value of the variable can't be written to the stream instead when the class is retrieved from the ObjectStream the value of the variable becomes null.