Javabean and Enterprise Javabean: What is the difference? MIKE DAYIBM Object Middleware Marketing Group July 1999
Editor's Note: The following is based on the round table discussion. Participants include the IBM "Component Agent" Beta Support Group's Ken Burget, Liane Acker, Jim Knutson, and David Morrill of IBM Enterprise Java Bean Development Division.
You may now use Javabean, but you still don't understand it. If you have a browser that supports Java, there is no limit on using JavaBean on your desktop. The web page that can be used as part of the small application. You will soon interact with Javabean as a browser visual part, then those JavaBeans will be with the EJB interface on the server. This capability can also be extended to the Internet. JavaBean and Server Beans (commonly referred to as Enterprise Javabean (EJB)) have some substantially the same. They are all created with a set of features to perform objects or components of their specific tasks. They also have the ability to achieve other features from the currently reside server. This makes the behavior of beans vary depending on the specific tasks and the environment. This has opened up a huge business opportunity. Because JavaBean is independent of the platform, for future solutions, suppliers can easily introduce their clients' JavaBean without having to create or maintain different versions. These JavaBeans can be used in conjunction with EJBs that perform business features such as ordering, credit card processing, electronic remittance, inventory assignment, transportation, etc.). There is a huge potential here, which is the potential for the design of the component agent (WebSphere Application Server Enterprise). JavaBean is a component that has an interface or has an attribute associated therewith so that the beans developed in different people at different times can ask and integrate. A bean can be constructed, and it is bound to other beans during later configuration. This process provides the method constructed first, then reuses the method, this is the concept of the component. This single application can be deployed as a standalone program, ActiveX component, or in the browser. JavaBean is different from the pure object due to its external interface (ie, attribute interface). This interface allows tool to read components to be executed, hook them with other beans, and insert them into other environments. JavaBean is designed to be locally in a single process, and they are often visible at runtime. This visual component may be a button, a list box, a graphic or chart - but it is not required. Executable Component Server Beans or EJB is an executable component or business object deployed on the server. There is a protocol to allow remote access to or install or deploy them on a specific server. A series of mechanisms allow them to authorize the main aspects of service security, transactional behavior, and concurrency (capacity of multiple clients), and persistence (which can be saved for a long time) to its container on the EJB server. When installed in the container, they obtain their respective behaviors, which provides different quality services, so selecting the correct EJB server is critical. This is the advantage of IBM WebSphere Enterprise Edition. EJB is a non-visual remote object designed to run on the server and is called by the client. EJB can be constructed by multiple non-visual JavaBeans. They have a deployment descriptor whose purpose is the same as the JavaBean property: it is a description of the bean that can be read by the tool later. EJB is still independent of the platform, once written, can also be used on any platform that supports Java (including clients and servers). Because EJB is generated by tools such as IBM Visualage for Java, it is based on server-based objects and is used for remote calls. They are installed on the EJB server and is like a remote interface that is called as calling other CORBA remote objects.
ActiveX objects can deploy JavaBean as an ActiveX object, although EJB agents can do this, but because ActiveX is running on the desktop, the EJB itself cannot be an ActiveX object. To do this with the platform, only Windows platforms do this, developers can transform JavaBeans to ActiveX components. Benefits EJB The main benefit is that when building beans, Bean developers can specify what type of behavior does not have to specify how to do it. Development is divided into two parts: programmers develop beans, then verify: it can work with the build tool and include deployment descriptors that identify the desired service quality behavior. Next, another programmer can use this bean and use the deployment tool for reading the EJB deployment descriptor, and then install the bean into the container on Enterprise Java Server. In the second step, the deployment tool takes some operations - this may mean that generate a status saving code, put transaction hook, or perform security check such a code. All of these operations are generated by deployment tools, Bean developers and deployers can be different. You can rewrite any platform-specific JavaBean to meet the specific needs of the existing business systems and applications by using deployment tools. This is why the EJB server is so important for integrated systems, networks, and architectures. EJB and IBM WebSphere Enterprise Edition When used in IBM WebSphere Enterprise Edition, the EJB can be configured as managed commercial objects. The container that accepts their authorization services is the container installed. Map the EJB's persistence section is mapped in the data or status object. The EJB server provides different quality of service for EJB, selecting the correct EJB server, may be critical to meeting full business needs. The Component Agent feature is extremely robust, which provides advanced features such as load balancing and supporting multiple machines in the server group. It also has a system management capabilities advocated by the Enterprise Java Server (EJS). Therefore, JavaBean or EJB written in accordance with basic standards can run on WebSphere Enterprise Edition using the Component Agent feature and get all additional features. The EJB server also provides unique features and quality of service, and is not exactly the same. IBM "Component Agent" has some powerful features - for example, scalability, which allows developers to deploy EJB to different types of servers from small systems to large networks. Developers can start from a small place, for example, in a department, first deploying on the Java server of the LAN, once ready, JavaBean and EJBs that can be created there should be deployed to a global network. Then, developers can test and familiar with these beans, trial operation, making samples, and more. After satisfaction, the developer can greatly expand its scale by moving it to a high performance server. JavaBean and EJB are not limited by any computer architecture boundary. They are written in Java, which can be run on any system with Java virtual machines and can use any Enterprise Java Server (EJS) to deploy objects. Therefore, developers can now build on a convenient system, and will be deployed on a convenient system without having to be the same or same type of machine. IBM WebSphere Enterprise Edition supports deployment of commercial objects to multiple servers. EJB is integrated into the "Component Agent" function as a business object and processes any other commercial objects. Therefore, EJB can be connected to the selected backend system and perform any desired operation to meet its business needs.
