BEA WebLogic Server 7 is the most widely adopted J2EE application server that is fully compliant with the industry-standard Java 2 Enterprise Edition version 1.3 platform, the programming model of choice for server-side development of enterprise-class applications. WebLogic Server also implements the J2EE Connector Architecture (J2CA), which enables developers to connect Enterprise Information Systems (EISs) to the J2EE platform and to apply J2EE component models, transactions, and security infrastructures toward the integration of these systems. Table 9.1 shows the full list of J2EE application programming interfaces (APIs) and other leading Internet technology standards supported by WebLogic Server. Table 9.1. J2EE 1.3 APIs and Other Leading Internet Technology Standards Supported by WebLogic Server
Full compliance with the J2EE platform and the leading Internet standards ensures that applications built and deployed on WebLogic Server have the following capabilities:
Unlike the J2EE standard, however, an application server is a commercial software product that different vendors develop and sell. All application server vendors must make sure their products are certified and fully compliant with the J2EE platform (see Figure 9.4) by ensuring the following: Figure 9.4. The J2EE platform specification.
J2EE is to the application server what SQL is to the relational database management system (RDBMS). Does implementing SQL imply that an RDBMS product provides all the services and features required by today's enterprises ? It does not. Oracle, Sybase, Microsoft, and other leading database vendors use SQL to provide a common access language to their products only. Everything else, such as the reliability, availability, and scalability of their products, is designed and implemented based on their efforts to be competitively aligned with the features a high percentage of organizations (customers) are seeking from relational database management systems. By forecasting and successfully satisfying these customer feature requirements, these software vendors gain leadership and a competitive edge in their product space. Likewise, the J2EE specification standardizes only the Java APIs (contracts) between components and the application server containers, and is nothing more than a definition of application infrastructure services. It is a common misconception to think that the J2EE specification covers all aspects of application infrastructure. It does not! For this reason, it is the responsibility of the application server vendors to implement the J2EE specification in an application infrastructure that also supports nonfunctional and Quality of Service (QoS) attributes, such as the following:
The degree to which an application server satisfies these non-J2EE and QoS attributes is what distinguishes it as a market leader. |