CHOOSING ENTITY BEANS OR STATEFUL SESSION BEANS

CHOOSING ENTITY BEANS OR STATEFULSESSION BEANS

 Now, we will learn when and where we should use entity beans or stateful session beans. The architect of the application chooses how to map the business entities and processes to

DIFFERENCE BETWEEN SESSION BEANS AND ENTITY BEANS

DIFFERENCE BETWEEN SESSION BEANS AND ENTITY BEANS

To understand whether a business process or business entity should be implemented as a

stateful session bean or an entity bean, it is important to understand the life-cycle and

DISADVANTAGE OR RESTRICTIONS OF EJB

DISADVANTAGE OR RESTRICTIONS OF EJB

Enterprise Java Beans have several restrictions, which they must adhere to:
1. They cannot create or manage threads.
2. They cannot access threads using the java.io package.
3. They cannot operate directly with sockets.
4. They cannot load native libraries.
5. They cannot use the AWT to interact with the user.
6. They can only pass objects and values which are compatible with RMI/IIOP.
7. They must supply a public no argument constructor.
8. Methods cannot be static or final.
9. There are more minor restrictions.

But following can be done with EJB:
1. Subclass another class.
2. Interfaces can extend other interfaces, which are descendants of EJBObject or
EJBHome.
3. Helper methods can pass any kind of parameters or return types within the EJB.
4. Helper methods can be any kind of visibility

SERVICES OFFERED BY EJB

SERVICES OFFERED BY EJB

JSP, Servlets and JavaBeans and EJBs have their own web container. The container of
EJB provides certain built-in services to EJBs, which is used by EJBs to perform different

ARCHITECTURE OF AN EJB/ CLIENT SYSTEM

ARCHITECTURE OF AN EJB/ CLIENT SYSTEM

There are various architectures of EJB (J2EE) available which are used for various
purposes. J2EE is a standard architecture specifically oriented to the development and

UNIT 2 ENTERPRISE JAVA BEANS: ARCHITECTURE AND GOALS

UNIT 2 ENTERPRISE JAVA BEANS: ARCHITECTURE AND GOALS

The EJB Specifications try to meet several goals which are described as following:
 

• EJB is designed to make it easy for developers to create applications, freeing them
from low-level system details of managing transactions, threads, load balancing,
and so on. Application developers can concentrate on business logic and leave the
details of managing the data processing to the framework. For specialised
applications, though, it's to customise these lower-level services.
 

• The EJB Specifications define the major structures of the EJB framework, and then
specifically define the contracts between them. The responsibilities of the client, the
server, and the individual components are all clearly spelled out. A developer
creating an Enterprise JavaBean component has a very different role from someone
creating an EJB-compliant server, and the specification describes the
responsibilities of each.
 

• EJB aims to be the standard way for client/server applications to be built in the Java
language. Just as the original JavaBeans (or Delphi component etc.) from different
vendors can be combined to produce a custom client, EJB server components from
different vendors can be combined to produce a custom server. EJB components,
being Java classes, will of course run in any EJB-compliant server without
recompilation. This is a benefit that platform-specific solutions cannot offer.
 

• Finally, the EJB is compatible with and uses other Java APIs, can interoperate with
non-Java applications, and is compatible with CORBA

SOLUTIONS/ANSWERS

SOLUTIONS/ANSWERS

1) Enterprise JavaBeans extends the JavaBeans component model to handle the needs
of transactional business applications.

what is entity bean and its ejb types

 what is entity bean and its ejb types

EJBs are distinguished along three main functional roles. Within each primary role, the
EJBs are further distinguished according to subroles. By partitioning EJBs into roles, the

BASIC EJB EXAMPLE

BASIC EJB EXAMPLE

To create an EJB we need to create Home, Remote and Bean classes.
 

Home Interface
 

EJB ARCHITECTURE

EJB ARCHITECTURE

The Enterprise JavaBeans spec defines a server component model and specifies, how to
create server-side, scalable, transactional, multiuser and secure enterprise-level components. Most

WHAT IS EJB?

WHAT IS EJB?

Enterprise JavaBeans are software component models, their purpose is to build/support
enterprise specific problems. EJB - is a reusable server-side software component.

JAVABEAN CONCEPTS

JAVABEAN CONCEPTS

JavaBeans is a complete component model. It supports the standard component
architecture features of properties, events, methods, and persistence. In addition, JavaBeans provides

UNIT 1 INTRODUCTION TO JAVA BEANS

UNIT 1 INTRODUCTION TO JAVA BEANS 

JavaBeans are software component models. A JavaBean is a general-purpose component
model. A Java Bean is a reusable software component that can be visually manipulated in

INTEGRATING SERVLET AND JSP

INTEGRATING SERVLET AND JSP

As you have seen, servlets can manipulate HTTP status codes and headers, use
cookies, track sessions, save information between requests, compress pages, access
 

INCLUDING FILES AND APPLETS IN JSP DOCUMENTS

INCLUDING FILES AND APPLETS IN JSP

DOCUMENTS

Now in this section, we learn how to include external pieces into a JSP document. JSP
has three main capabilities for including external pieces into a JSP document.

UNIT 4 JAVA SERVER PAGES-II DATABASE HANDLING IN JSP

UNIT 4 JAVA SERVER PAGES-II DATABASE HANDLING IN  JSP  

We have already seen how to interface an HTML Form and a JSP. Now, we have to
see how that JSP can talk to a database. In this section, we will understand how to: