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Question 1 :

What are the two important TCP Socket classes?

Answer :

Socket and ServerSocket.
ServerSocket is used for normal two-way socket communication. Socket class allows us to read and write through the sockets. getInputStream() and getOutputStream() are the two methods available in Socket class.

Question 2 :

What technologies are included in J2EE?

Answer :

The main technologies in J2EE are: Enterprise JavaBeansTM (EJBsTM), JavaServer PagesTM (JSPsTM), Java Servlets, the Java Naming and Directory InterfaceTM (JNDITM), the Java Transaction API (JTA), CORBA, and the JDBCTM data access API.

Question 3 :

What is the difference between EJB and Java beans?

Answer :

EJB is a specification for J2EE server, not a product; Java beans may be a graphical component in IDE.

Question 4 :

What is EJB role in J2EE?

Answer :

EJB technology is the core of J2EE. It enables developers to write reusable and portable server-side business logic for the J2EE platform.

Question 5 :

Tell me something about Local Interfaces?

Answer :

EJB was originally designed around remote invocation using the Java Remote Method Invocation (RMI) mechanism, and later extended to support to standard CORBA transport for these calls using RMI/IIOP. This design allowed for maximum flexibility in developing applications without consideration for the deployment scenario, and was a strong feature in support of a goal of component reuse in J2EE. Many developers are using EJBs locally, that is, some or all of their EJB calls are between beans in a single container. With this feedback in mind, the EJB 2.0 expert group has created a local interface mechanism. The local interface may be defined for a bean during development, to allow streamlined calls to the bean if a caller is in the same container. This does not involve the overhead involved with RMI like marshalling etc. This facility will thus improve the performance of applications in which co-location is planned. Local interfaces also provide the foundation for container-managed relationships among entity beans with container-managed persistence.