The difference between JavaBeans and EJB

Source: Internet
Author: User
Tags websphere application server

You may be using Javabeans now, but you don't know it yet. If you have a Java-enabled browser, there is no limit to using Javabeans on your desktop. The Web page you use can beans as part of a small application. You will soon interact with the Javabeans as a visual part of the browser, and then those Javabeans will be with the EJB interface on the server. This capability can also be extended to the Internet and intranet.

Javabeans and Server beans (commonly referred to as Enterprise Javabeans (EJB)) have some basic similarities. They are objects or components that are created with a set of attributes to perform their specific tasks. They also have the ability to obtain additional features from the containers currently residing on the server. This makes the behavior of beans different depending on the specific task and the environment in which it is located.

This opens up huge business opportunities. Because Javabeans is platform-independent, for future solutions, vendors can easily roll out their client-side Javabeans to different users without having to create or maintain different versions. These Javabeans can be used in conjunction with EJBS that perform commercial functions such as ordering, credit card processing, electronic remittance, inventory allocation, transportation, and so on. There is tremendous potential, which is the kind of potential that the component agent (WebSphere Application Server Enterprise Edition) design offers.

Javabeans is a component that has interfaces or attributes associated with it internally, so that beans that different people develop at different times can be queried and integrated. You can build a beans and bind it to other beans later when it is constructed. This process provides a way to build and then reuse, which is the concept of the component. You can deploy such a single application as a stand-alone program, an ActiveX component, or in a browser.

Javabeans is different from a pure object because of its external interface (that is, the property interface). This interface allows the tool to read the function to be performed by the component, hook it up with other beans, and insert it into other environments. Javabeans are designed to be local to a single process and are usually visible at run time. This visual component may be a button, list box, graphic, or chart-but this is not required.

An ActiveX object can deploy Javabeans as an ActiveX object, although the EJB proxy can do so, but because ActiveX runs on the desktop, the EJB itself cannot be an ActiveX object. To do this on a platform-dependent, Windows-only platform, developers can transform Javabeans into ActiveX components.

The main benefit of EJBS is that when building beans, beans developers can specify what type of behavior is required without having to prescribe how to do it. Development is divided into two parts: the programmer develops the beans, and then verifies that it works with the build tools and includes a deployment descriptor that identifies the type of service quality behavior that is required. Next, another programmer can take this beans and use the deployment tool that reads the EJB deployment descriptor and then install the beans into a container on Enterprise Java Server. In the second step, the deployment tool takes some action, which may mean generating code such as state-saving code, placing a transaction hook, or performing a security check. All of these operations are generated by the deployment tools, and beans developers and deployment personnel can be different people.

You can use deployment tools to rewrite any platform-independent Javabeans into a reliable quality of service, platform-specific EJB to meet the specific needs of existing business systems and applications. This is why EJB servers are so important to integrated systems, networks, and architectures.

EJB and IBM WebSphere Enterprise Edition:

When used in IBM WebSphere Enterprise Edition, EJB can be configured as a managed business object. The container that accepts the services they authorize is the container to which they are installed. Maps the persistence portion of an EJB to a data or state object. EJB servers provide a different quality of service for EJBS, and choosing the right EJB server may be critical to satisfying a complete business requirement. The component Agent feature is extremely robust and provides advanced functionality such as load balancing and multiple machines in a server group. It also has much more system management capabilities than is advocated by the Enterprise Java Server (EJS) specification. As a result, Javabeans or EJBS written according to basic standards can run on the WebSphere Enterprise Edition that uses the component Agent feature and get all of the additional functionality.

The EJB server also provides unique features and quality of service, and is not exactly the same. The IBM component agent has some powerful features-for example, scalability, which allows developers to deploy EJBS to different types of servers from small systems to large networks. Developers can start small, for example, in one department, first deployed on a LAN's Java server and, once ready, know that Javabeans and EJBs created there can be deployed to the global network. Then, developers can test and familiarize themselves with these beans, test runs, sample making, and so on.

When satisfied, developers can dramatically scale up by moving it to a high-performance server. Javabeans and EJBs are not limited by any computer architecture boundaries. They are written in Java and can be run on any system that has a Java virtual machine and can deploy objects using any Enterprise java Server (EJS). As a result, developers can now build on a convenient system and later deploy on a convenient system without having to be the same machine or the same type.

IBM WebSphere Enterprise Edition supports the deployment of business objects to multiple servers. EJB is integrated into the component broker function as a business object and processed as any other business object. As a result, EJBS can connect to the selected backend system and perform any required operations to meet their business needs. This becomes the infrastructure that the component agent provides for EJBS. By using the component agent as an EJB server, developers will be able to continue to use the current legacy system and provide it with an e-business interface.

To enable the EJB to work in the WebSphere Component Agent environment, you can use the Component Agent Deployment tool to install it on one or more servers and then add it to a named server so that it can be found globally. Anyone who can access a public naming server can find it, find its host, and execute methods on the host, creating EJBS as well. This is what the agent component is going to do.

Let's cite an example of an electronic shopping cart that can be seen on a web shopping site. The user's shopping cart is a Javabeans. The user puts the goods on the shelves into the shopping cart, the goods themselves are Javabeans. They are all visible and user-oriented. When checkout, send the items in the user's shopping cart to the EJB on the server, the EJB performs the necessary operations, such as checking credit card authorization and availability, generating seals, or generating special instructions to the shipping department regarding the delivery and delivery location, which is what the business process is already doing.

The full significance of beans is not only its existing ability, but also its potential ability to provide business with competitiveness. It architects and application developers can now focus exclusively on business logic, leaving the underlying work, such as transaction, persistence, and security, to the server. The component Agent feature of WebSphere will provide all these (and backend access) and object transaction managers.

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