The document discusses Enterprise Java Beans (EJB), which are server-side components that contain business logic in Java EE applications. It describes the different types of EJBs - entity beans, session beans, and message-driven beans. It also outlines the key parts of an EJB including the home, remote, and bean class interfaces as well as the deployment descriptor. Finally, it provides an example of an Account EJB and discusses how J2EE provides common services to bundle application components.
TUTORIAL-INTRODUCTION TO SPRING FOR BEGINNERS
EXPLANATION TO-Java Framework,Advantages of using SPRING,Difference between Hibernate and Spring.Spring architecture,Spring IoC Containters,Bean scope & Method Injection,Spring Inheritance.
TUTORIAL-INTRODUCTION TO SPRING FOR BEGINNERS
EXPLANATION TO-Java Framework,Advantages of using SPRING,Difference between Hibernate and Spring.Spring architecture,Spring IoC Containters,Bean scope & Method Injection,Spring Inheritance.
To better understand the behavior of servlets, let’s take a look at the life cycle of servlets.
A servlet is basically a small Java program that runs within a Web server. It can receive requests from clients and return responses. The whole life cycle of a servlet breaks up into 3 phases:
• Initialization: A servlet is first loaded and initialized usually when it is requested by the corresponding clients. Some websites allow the users to load and initialize servlets when the server is started up so that the first request will get responded more quickly.
• Service: After initialization, the servlets serve clients on request, implementing the ap- plication logic of the web application they belong to.
• Destruction: When all pending requests are processed and the servlets have been idle for a specific amount of time, they may be destroyed by the server and release all the resources they occupy.
More specifically, the behavior of a servlet is described in javax.servlet.Servlet interface, in which the following methods are defined:
• public void init(ServletConfig config) throws ServletException
This method is called once when the servlet is loaded into the servlet engine, before the servlet is asked to process its first request.
The init method has a ServletConfig parameter. The servlet can read its initialization arguments through the ServletConfig object. How the initialization arguments are set is servlet engine dependent but they are usually defined in a configuration file.
A typical example of an initialization argument is a database identifier. A servlet can read this argument from the ServletConfig at initialization and then use it later to open a connection to the database during processing of a request:
private String databaseURL;
public void init(ServletConfig config) throws ServletException { super.init(config);
databaseURL = config.getInitParameter("database");
}
• public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException
This method is called to process a request. It can be called zero, one or many times until the servlet is unloaded.
Once a servlet is loaded, it remains in the server’s memory as a single object instance. Thereafter, the server invokes the servlet to handle a request using a simple, lightweight method invocation. Unlike with CGI, there’s no process to spawn or interpreter to invoke, so the servlet can begin handling the request almost immediately. Multiple, concurrent requests are handled by separate threads, so servlets are highly scalable.
Servlets are naturally enduring objects. Because a servlet stays in the server’s memory as a single object instance, it automatically maintains its state and can hold on to external resources, such as database connections, that may otherwise take several seconds to establish. The following servlet presents information about how many times it has been accessed:
To better understand the behavior of servlets, let’s take a lo
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9. Distribute the VOR to colleagues for noncommercial scholarly use, provided those receiving copies are informed that they may not further copy or distribute the Work.
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Each Author and Copyright Owner represents and warrants to AIP Publishing the following:
1. The Work is the original independent creation of each Author and does not infringe any copyright or violate any other right of any third party.
2. The Work has not been previously published and is not being considered for publication elsewhere in any form, except as a preprint on a noncommercial server such as arXiv, or in a thesis or dissertation.
3. Written permission has been obtained for any material used from other sources and copies of the permission grants have been supplied to AIP Publishing to be included in the manuscript file.
4. All third-party material for which permission has been obtained has been properly credited within the manuscript.
5. In the event that the Author is subject to university open access policies or other institutional restrictions that conflict with any of the rights or provisions of this License, such Author has obtained the necessary waiver from his or her university or institution.
This License must be signed by the Author(s) and, in the case of a Work Made for Hire, also by the Copyright Owners. One Author/Copyright Owner may sign on behalf of all the contributors/owners only if they all have authorized the signing, approved of the License, and agreed to be bound by it. The signing Author and, in the case of a Work Made for Hire, the signing Copyright Owne
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2. 9/11/2023 B.Ramamurthy 2
Introduction
J2EE (Java2 Enterprise Edition) offers a
suite of software specification to design,
develop, assemble and deploy
enterprise applications.
It provides a distributed, component-
based, loosely coupled, reliable and
secure, platform independent and
responsive application environment.
3. 9/11/2023 B.Ramamurthy 3
J2EE Technologies
Enterprise Java Bean Technology 2.0
JDBC API 2.0
Java Servlet Technology 2.3
Java Server Pages Technology 1.2
Java Messaging Service 1.0
Java Naming and Directory Interface 1.2
Java Transaction API 1.0
Java Mail API 1.2
Javabeans activation framework 1.0
Java API for XML Processing 1.1
Java Connector Architecture 1.0
Java Authentication and Authorization Service 1.0
Tools: deploytool (scripts etc.)
4. 9/11/2023 B.Ramamurthy 4
Systems and Application
Integration
The J2EE APIs enable systems and
applications integration through the following:
Unified application model across tiers with
enterprise beans
Simplified response and request mechanism with
JSP pages and servlets
Reliable security model with JAAS
XML-based data interchange integration with JAXP
Simplified interoperability with the J2EE Connector
Architecture
Easy database connectivity with the JDBC API
Enterprise application integration with message-
driven beans and JMS, JTA, and JNDI
5. 9/11/2023 B.Ramamurthy 5
J2EE Technology Architecture
Server
platform
JTS JMAPI JNDI JMS JDBC
JAXP JAAS …
Enterprise Java Beans Components
Java Server
pages
Servlets
Application clients Web clients
IIOP,
others
html
6. 9/11/2023 B.Ramamurthy 6
Enterprise Java Bean(EJB)
An enterprise bean is a server-side
component that contains the business logic of
an application. At runtime, the application
clients execute the business logic by invoking
the enterprise bean's methods.
Main goal of Enterprise Java Bean (EJB)
architecture is to free the application
developer from having to deal with the
system level aspects of an application. This
allows the bean developer to focus solely on
the logic of the application.
7. 9/11/2023 B.Ramamurthy 7
Roles in EJB Development
Bean developer: Develops bean component.
Application assembler: composes EJBs to form
applications
Deployer: deploys EJB applications within an
operation environment.
System administrator: Configures and administers the
EJB computing and networking infrastructure.
EJB Container Provider and EJB server provider:
Vendors specializing in low level services such as
transactions and application mgt.
8. 9/11/2023 B.Ramamurthy 8
Enterprise Java Bean (EJB)
Deployable unit of code.
At run-time, an enterprise bean resides in an
EJB container.
An EJB container provides the deployment
environment and runtime environment for
enterprise beans including services such as
security, transaction, deployment,
concurrency etc.
Process of installing an EJB in a container is
called EJB deployment.
9. 9/11/2023 B.Ramamurthy 9
Enterprise Application with
many EJBs
WebClient
ApplClient
EJB1
EJB2
EJB3
EJB4
EJB5
EJB6
Lets consider a shopping front application and figure out the
possible components (EJBs)
11. 9/11/2023 B.Ramamurthy 11
Business Entities, Processes
and Rules
EJB Applications organize business rules into
components.
Components typically represent a business
entity or business process.
Entity: is an object representing some
information maintained in the enterprise. Has
a “state” which may be persistent.
Example: Customer, Order, Employee,
Relationships are defined among the entities:
dependencies.
12. 9/11/2023 B.Ramamurthy 12
Process
Is an object that typically encapsulates an interaction
of a user with business entities.
A process typically updated and changes the state of
the entities.
A business process may have its own state which
may exist only for the duration of the process; at the
completion of the process the state ceases to exist.
Process state may be transient or persistent.
States ate transient for conversational processes and
persistent for collaborative processes.
13. 9/11/2023 B.Ramamurthy 13
Rules
Rules that apply to the state of an
entity should be implemented in the
component that represents the entity.
Rules that apply to the processes
should be implemented in the
component that represents the
processes.
14. 9/11/2023 B.Ramamurthy 14
EJB Types
There are three types of EJBs:
Entity, session and message-driven
We will discuss message-driven bean in a
separate discussion.
The syntax of the session bean and entity
bean client-view API is almost identical.
But they have different life cycle, different
persistence management, etc.
EJBs can be stateless and stateful beans.
15. 9/11/2023 B.Ramamurthy 15
Life Cycle Differences
Session Bean
Object state:
Maintained by container
Object Sharing:
No sharing: per client
State Externalization:
State is inaccessible to other
programs
Transactions:
Not recoverable
Failure Recovery:
Not guaranteed to survive failures
Entity Bean
Maintained by DB
Shared by multiple client
Accessible to other programs
State changed transactionally and
is recoverable.
Survives failures and restored when
the container restarts.
16. 9/11/2023 B.Ramamurthy 16
Choosing Entity or Session
Bean
Entity (business entity) is typically implemented as
entity bean or a dependent object of an entity bean.
Conversational (business) process as a session bean.
Collaborative bean as an entity bean.
Any process that requires persistence is implemented
as an entity bean.
When exposure to other applications are not needed
for an entity or process (local/private process) then
they are implemented as bean dependent objects.
17. 9/11/2023 B.Ramamurthy 17
Parts of EJB
EJB class that implements the business methods
and life cycle methods; uses other helper
classes and libraries to implement.
Client-view API: consists of EJB home interface
and remote interface.
Home interface: controls life cycle : create, remove,
find methods
Remote interface: to invoke the EJB object methods
18. 9/11/2023 B.Ramamurthy 18
Parts of EJB (contd.)
Deployment Descriptor: XML document for
bean assembler and deployer;
A declaration about EJB environment needed for
customizing the bean to the operating
environment.
Container Runtime services include:
transactions, security,distribution,load
balancing, multithreading, persistence, failure
recovery, resource pooling, state
management, clustering..
19. 9/11/2023 B.Ramamurthy 19
Enterprise Bean Parts
<<Home Interface>>
AccountHome
create()
find()
remove()
<<Remote Interface>>
Account
debit()
credit()
getBalance()
<<Enterrpise Bean class>
AccountBean
ejbCreate()
ejbFind()
ejbRemove()
debit()
credit()
getBalance()
Deployment Descriptor
name = AccountEJB
class = AccountBean
home = AccountHome
remote = Account
type = Entity
transaction = required
…..
22. 9/11/2023 B.Ramamurthy 22
AccountBean class
public class AccountBean implements javax.ejb.EntityBean {
// life cycle methods from home interface
public AccountKey ejbCreate (String latName, String firstName) throws … {…
public AccountKey ejbCreate(String lastName) throws …{…}
public AccountKey ejbFindByPrimaryKey(AccountKey primarykey)… {…}
Public Collection ejbFindInactive( Data sinecWhen).. {…}
// business methods from remote interface
public BigDecimal getBalance() {….}
public void credit(BigDecimal amt) {…}
Public void debit(BigDecimal amt) throws InsufficientFundException {….}
// container callbacks from EntityBean container
public ejbRemove( ) throws RemoveException{ …}
public void setEntityContext(EntityContext ec) {…}
public unsetEntityContext(EntityContext ec) {…}
public void ejbActivate() {…}
public void ejbLoad() {….}
public void ejbStore() {….}
}
24. 9/11/2023 B.Ramamurthy 24
Summary
J2EE environment provides a framework for
bundling together the components into an
application and provide the applications
necessary common services such as
persistence, security, mail, naming and
directory service etc.
Next class we will look a complete running
example.
Browse through:
http://java.sun.com/j2ee/faq.html
http://java.sun.com/blueprints/guidelines/designing_en
terprise_applications_2e/index.html#chapters