Polymorphism 1-3

Table Model interface used for implementaion of jtable

Socket API unix domain

Serlvelt infterface is the top abstraciton level.

Java can send icmp packet

Custmo class loader use to load serlvet repaealtid

Getbinary stream is use to get binary data.

Jsessionid is the cookie that maintains sessionn.

Skeleton object is use GET VALUE OR EXCEPTION

The rmic compiler generates the stub and skeleton classes for remote objects you’ve written

EJB class, home and remote interfaces are needed for session ejb and entity.

one servlet instance per registered servlet name, is correct library.

Message-Driven Bean ClassIt implements the MessageDrivenBean and MessageListener interfaces.

Remote object access java.rmi.Remote interface

Serlvelt interface is a

ServletContextListener is a interface which contains two methods:

  1. public void contextInitialized(ServletContextEvent event)
  2. public void contextDestroyed(ServletContextEvent event)

Entity beans:
Entity beans are enterprises beans, which represent persistent data stored in a storage medium, such as relational database an entity bean persists across multiple session and can be accessed by multiple clients. An entity bean acts as an intermediary between a client and a database. For example, consider a bank entity bean that is used for accessing account details from a database. When a client wants to perform a transaction, the information regarding their specific account is loaded into an entity bean instance from the database. Operations are performed on the data present in the instance and updated in the banks database at regular intervals.
ServletConfig: The object created after a servlet is instantiated and its default constructor is read. It is created to pass initialization information to the servlet.

Defines an object to provide client request information to a servlet. The servlet container creates a ServletRequest object and passes it as an argument to the servlet’s service method.

Interspection in bean

Introspection is the ability to ask a JavaBean component what properties and events it supports. By default, introspection is supported by reflection, where you name methods with certain naming patterns, like set/getProperty() and add/removeListener(). You can also explicitly expose the bean’s behavior through creation of a BeanInfo class related to the bean. The BeanInfo class can be used for many things, like setting up an icon for the component when used in a bean builder tool like JBuilder, limiting the properties available, or mapping methods to properties that don’t follow standard naming patterns.

What is a remote interface?

According to RMI specification, a remote interface is an interface that extends java.rmi.Remote interface and declares a set of methods that may be invoked from a remote Java Virtual Machine(JVM). Note that the java.rmi.Remote interface serves as a mark to tell the system that methods declared within this interface may be invoked from a non-local virtual machine.

What is the difference between activation and passivation

Answered by Jey on 2005-05-08 11:55:29:

Activation and Passivation is appilicable for only Stateful session bean and Entity bean.

When Bean instance is not used for a while by client then EJB Container removes it from memory and puts it in secondary storage (often disk) so that the memory can be reused. This is called Passivation.

When Client calls the bean instance again then Container takes the passivated bean from secondary storage and puts it in memory to serve the client request. This is called Activation.

Default erro number in case of servlet is 500

  • doGet, if the servlet supports HTTP GET requests
  • doPost, for HTTP POST requests
  • doPut, for HTTP PUT requests
  • doDelete, for HTTP DELETE requests
  • init and destroy, to manage resources that are held for the life of the servlet
  • getServletInfo, which the servlet uses to provide information about itself

Serlvelte loding proceess



message bean dilver class.

cover all topics of beans

what is enterprise bean.

Bussiness delegate

you want to hide clients from the complexity of remote communication with business service components.


  • You want to access the business-tier components from your presentation-tier components and clients, such as devices, web services, and rich clients

e Data Access Object (DAO) layer is an essential part of good application architecture. Business applications almost always need access to data from relational or object databases and the Java platform offers many techniques for accessing this data. The oldest and most mature technique is to use the Java Database Connectivity (JDBC) API, which provides the capability to execute SQL queries against a database and then fetch the results, one column at a time. Although this API provides everything a developer needs to access data and to persist application state, it is a cumbersome API to develop against – which makes a code generator particularly useful.

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