The Geek's Blog

A building block to execute the business logic. Types Entity beans Enterprise beans Message driven Beans Enterprise beans use the databases if required The most important benefit of the enmity bean is that it doesn't need any code for JDBC connection API EJB container itself handles the same. If we have a need to use session bean to use the database we need to implement the JDBC connection code.

The entire Web Development Process has following steps to be followed. Purchase and installation of J2EE products and tools. J2EE components can be developed by application component providers. Assembled by application assemblers. Deployed by application deployers.   J2EE Product Provider Product providers are typically operating system, database system, application server, or web server vendors who implement the J2EE platform according to the Java 2 Platform, Enterprise Edition specification.   Tool Provider The tool provider is the company or person who creates development, assembly, and packaging tools used by component providers, assemblers, and deployers.   Application Component Provider The application component provider is the company or person who creates web components, enterprise beans, applets, or application clients for use in J2EE applications.   Enterprise Bean Developer An enterprise bean developer performs the following tasks to deliv...

The enterprise application is delivered to the client as a .ear file having a no of .jar files, settings, other libraries , deployment descriptors and other web resources. A deployment descriptor is an XML document with an .xml extension that describes the deployment settings of an application, a module, or a component. At runtime the J2EE container reads the deployment descriptors and acts upon the application, module or component accordingly. Two types of Deployment descriptor J2EE Deployment Descriptors:-Defined by the J2EE Specification. It can be used to configure settings for any J2EE compliant implementation. Runtime Deployment Descriptors: - It is used to configure J2EE implementation specific parameters.

Web services are web-based enterprise applications that use open, XML-based standards and transport protocols to exchange data with calling clients. The J2EEplatform provides the XML APIs and tools you need to quickly design, develop, test, and deploy web services and clients that fully interoperate with other web services and clients running on Java-based or non-Java-based platforms. The translation of data to a standardized XML-based data stream is what makes web services and clients written with the J2EE XML APIs fully interoperable. It is not like one should pass data in the xml format but it can be any type of data like plain text, audio, video, maps, programme files.   XML XML is a cross-platform, extensible, text-based standard for representing data. It helps in reusability of the data being processed for Example One company might put XML pricing information through a program to translate the XML to HTML so that it can post the price lists to its intranet. A...

J2EE Containers Helps in separating the business logic and other mechanisms like Resource pooling , multi-threading and state management . Before Deployment Any Component is to be assembled to the J2EE container. Each assembly owns the settings for the container services like Security, Transaction management, JNDI, Remote Connectivity, etc. JNDI lookup services provide a unified interface to multiple naming and directory services in the enterprise so that application components can access naming and directory services. The J2EE remote connectivity model manages low-level communications between clients and enterprise beans. After an enterprise bean is created, a client invokes methods on it as if it were in the same virtual machine. Having configurable environment it can behave differently on different environment. Also provides some non-configurable services like data persistence, dB resource pooling, servlet lifecycle, Enterprise bean.   J2EE CONTAINER TYPES ...

Abstract Factory Design Pattern In software development, a  factory  is the location in the code at which objects are constructed.  The intent in employing the pattern is to insulate the creation of objects from their usage. This allows for new derived types to be introduced with no change to the code that uses the base class. The essence of the Abstract Factory method Pattern is to "Provide an interface for creating families of related or dependent objects without specifying their concrete classes". For Example: Address Factory has no of factories like: US Address Factory which implements the Address Interface. French Address Factory which implements the Address interface. Can have many more country specific factories…. When we create the French Address using the method implemented in the French Address Factory class it returns the Object reference to the Abstract class of Address. The Abstract Address class holds the ...

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