Q. What is Java?
Ans : Java is a programming language and computing platform.Java can be used to create complete applications that may run on a single computer or be distributed among servers and clients in a network. It can also be used to build a small application module or applet for use as part of a webpage.

Q. What are Java Servlets?
Ans : A servlet is a java program that executes on the server, accepting client requests and generating dynamic responses. Servlets do not just create HTML. Theses cal also be used to generate other MIME types, such as images.

Q. What is JSP (Java Server Pages)?
Ans : JSP are HTML documents that are interwoven with Java. JSP provides dynamic responses that is based on client request. JSP's are portable(write once, run everywhere). JSP's compile and run as servlets.

Q. What are EJBs (Enterprise Java Beans)? 
Ans :  EJBs are distributed components written in the java programming language.
EJBs provide distributable and deployable business services(Logic)to clients.
EJBs are reusable accross application servers.
EJBs execute within a container that provides management and control services.

Q. What is JDBC (Java Database Connectivity )?
Ans : Java Database Connectivity (JDBC) is an application programming interface (API) for the programming language Java, which defines how a client may access a database.
It is the standard java interface for accessing heterogeneous databases.

Q. What is JNDI (Java Naming and Directory Interface)?
Ans : JNDI is a Java API for a directory service that allows Java software clients to discover and look up data and objects via a name.It is an Java API for accessing naming and directory services.It built as a layer over DNS,LDAP and so on.

Q. What is JTA (Java Transaction API)?
Ans : JTA is a standard JAVA API that enables distributed transactions to be done across multiple X/Open XA resources in a Java environment.Java Transaction API (JTA) specifies standard Java interfaces between a transaction manager and the parties involved in a distributed transaction system: the resource manager, the application server, and the transactional applications.


Q. What is JMS (Java Messaging Service)?
Ans :  The Java Message Service is a Java API that allows applications to create, send, receive, and read messages.The JMS API defines a common set of interfaces and associated semantics that allow programs written in the Java programming language to communicate with other messaging implementations.The JMS API minimizes the set of concepts a programmer must learn in order to use messaging products but provides enough features to support sophisticated messaging applications.

Q. WHat is JAAS (Java Authentication & Autherization)?
Ans :  It is  a java based security management framework that supports single sign-on and a pluggable authentication Module(PAM).

Q. What is JMX (Java Management Extension)?
Ans : It defines a standard infrastructure to manage a device from java programs.MBEANS are the building blocks of JMX.

Q. What is JCA (Java Connector Architecture)?
Ans : JCA connects Enterprise Info. System(EIS) with resource adapters and resource adapters can be deployed in a Resource Adapter Archive(RAR).

Q. What is Client Application ?
Ans : The client application interacts with WLS through JRMP/T3, IIOP and jCOM.
The types of clients include :
a) Standalone java applications.
b) Applets within a browser.

Q. What is Web Client?
Ans : A web client interacts with oracle WLS via HTTP using servlets and JSPs.
The types of web clients includes :
a) Browser
b) Web Service(SOAP over HTTP)

Q. What is Proxy Server?
Ans : It forwards the requests to other machines. It can also be used to load balance a system.

Q. What is T3 protocol in WebLogic?
Ans :  T3 is an optimized protocol used to transport data between WLS and other java programs including clients and other WLS servers. WLS server keeps track of every JVM with which it connects and creates a single T3 connection to carry all traffic for a JVM.
T3 and T3s are proprietary protocols that are analogous to the industry standard HTTP or HTTPS protocols.