Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Java 2 Platform Enterprise Edition(J2EE) A Model for Enterprise Application Development Report from the Java Days Conference Athens,Greece 17/01/2002 Nikolaos Th. Korfiatis Research Assistant Information Systems Technologies Laboratory Department of Management Science and Technology Athens University of Economics and Business Athens, Greece

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business The Platform for Enterprise Solutions According to SUN the J2EE platform : According to SUN the J2EE platform : Represents a single standard for implementing and deploying enterprise applications. Represents a single standard for implementing and deploying enterprise applications. Has been designed through an open process. Has been designed through an open process. Is engaging a range of enterprise computing vendors, to ensure that it meets the widest possible range of enterprise application requirements. Is engaging a range of enterprise computing vendors, to ensure that it meets the widest possible range of enterprise application requirements. Addresses the core issues that impede organizations’ efforts to maintain a competitive place in the information economy. Addresses the core issues that impede organizations’ efforts to maintain a competitive place in the information economy.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business J2EE Architecture Overview The J2EE architecture is designed to provide server-side and client-side support for : Developing enterprise, multitier applications. Developing enterprise, multitier applications. Providing client services and business logic for an application, and backend enterprise information systems Providing client services and business logic for an application, and backend enterprise information systems Providing data and knowledge management. Providing data and knowledge management.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business J2EE Platform Benefits With a set of features designed specifically to expedite the process of distributed application development, the J2EE platform offers several benefits such as: Simplified architecture and development Simplified architecture and development Scalability to meet demand variations Scalability to meet demand variations Integration with existing information systems Integration with existing information systems Choices of servers, tools, components Choices of servers, tools, components Flexible security model Flexible security model

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Simplified Architecture and Development The J2EE platform supports a simplified, component-based development model. The J2EE platform supports a simplified, component-based development model. Because it’s based on the Java programming language and the Java 2 Platform, Standard Edition (J2SE TM platform), this model offers Write Once, Run Anywhere portability, supported by any server product that conforms to the J2EE standard. Because it’s based on the Java programming language and the Java 2 Platform, Standard Edition (J2SE TM platform), this model offers Write Once, Run Anywhere portability, supported by any server product that conforms to the J2EE standard. The component-based J2EE development model can enhance application development productivity in a number of ways The component-based J2EE development model can enhance application development productivity in a number of ways

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Simplified Architecture and Development Maps easily to application functionality: Maps easily to application functionality: Component-based application models map easily and flexibly to the functionality desired from an application. Component-based application models map easily and flexibly to the functionality desired from an application. Component-based design also simplifies application Component-based design also simplifies application maintenance, since components can be updated and maintenance, since components can be updated and replaced independently new functionality can be shimmed into existing applications simply by updating selected components. replaced independently new functionality can be shimmed into existing applications simply by updating selected components.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Simplified Architecture and Development (2) Enables assembly- and deploy-time behaviors: Enables assembly- and deploy-time behaviors: Components can expect the availability of standard services in the runtime environment, and can be dynamically connected to other components providing well-defined interfaces. Components can expect the availability of standard services in the runtime environment, and can be dynamically connected to other components providing well-defined interfaces. As a result, many application behaviors can be configured at the time of application assembly or deployment, without any recoding required. As a result, many application behaviors can be configured at the time of application assembly or deployment, without any recoding required.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Simplified Architecture and Development (3) Supports division of labor Supports division of labor Components help divide the labor of application development among specific skill sets, enabling each member of a development team to focus on his or her ability. Components help divide the labor of application development among specific skill sets, enabling each member of a development team to focus on his or her ability. Thus, JSP templates can be created by graphic designers, their behavior by Java programming language coders, business logic by domain experts, and application assembly and deployment by the appropriate team members. Thus, JSP templates can be created by graphic designers, their behavior by Java programming language coders, business logic by domain experts, and application assembly and deployment by the appropriate team members. This division of labor also helps expedite application maintenance. This division of labor also helps expedite application maintenance.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Integrating Existing Enterprise Information Systems The J2EE platform, together with the J2SE platform, includes a number of industry standard APIs for access to existing enterprise information systems. Basic access to these systems is provided by the following APIs: JDBC TM is the API for accessing relational data from Java. JDBC TM is the API for accessing relational data from Java. The Java Naming and Directory Interface TM (JNDI) is the API for accessing information in enterprise name and directory services. The Java Naming and Directory Interface TM (JNDI) is the API for accessing information in enterprise name and directory services. The Java Message Service (JMS) is the API for sending and receiving messages via enterprise messaging systems like IBM MQ Series and TIBCO Rendezvous. The Java Message Service (JMS) is the API for sending and receiving messages via enterprise messaging systems like IBM MQ Series and TIBCO Rendezvous. JavaMail TM is the API for sending and receiving . JavaMail TM is the API for sending and receiving . Java IDL is the API for calling CORBA services. Java IDL is the API for calling CORBA services.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Support for Business Logic Components In the J2EE platform, middle-tier business logic is implemented in the middle tier as Enterprise JavaBeans components (also referred to as enterprise beans). Enterprise beans allow the component or application developer to concentrate on the business logic while the complexities of delivering a reliable, scalable service are handled by the EJB server. In the J2EE platform, middle-tier business logic is implemented in the middle tier as Enterprise JavaBeans components (also referred to as enterprise beans). Enterprise beans allow the component or application developer to concentrate on the business logic while the complexities of delivering a reliable, scalable service are handled by the EJB server. The J2EE platform and EJB architecture have complementary goals. The EJB component model is the backbone of the J2EE programming model. The J2EE plat-form complements the EJB specification by: The J2EE platform and EJB architecture have complementary goals. The EJB component model is the backbone of the J2EE programming model. The J2EE plat-form complements the EJB specification by: Fully specifying the APIs that an enterprise bean developer can use to implement enterprise beans. Fully specifying the APIs that an enterprise bean developer can use to implement enterprise beans. Defining the larger, distributed programming environment in which enterprise beans are used as business logic components. Defining the larger, distributed programming environment in which enterprise beans are used as business logic components.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Scalability J2EE containers provide a mechanism that supports simplified scaling of distributed applications, without requiring any effort on the part of the application development team. Because J2EE containers provide components with transaction support, database connections, life cycle management, and other features that influence performance, they can be designed to provide scalability in these areas. This can achieved, by : J2EE containers provide a mechanism that supports simplified scaling of distributed applications, without requiring any effort on the part of the application development team. Because J2EE containers provide components with transaction support, database connections, life cycle management, and other features that influence performance, they can be designed to provide scalability in these areas. This can achieved, by : Providing database connection pooling so containers can ensure that clients will have access to data quickly. Providing database connection pooling so containers can ensure that clients will have access to data quickly. By allowing server providers freedom to configure containers to run on multiple systems. Web containers can be implemented to perform automatic load balancing as the demand for a particular application fluctuates. By allowing server providers freedom to configure containers to run on multiple systems. Web containers can be implemented to perform automatic load balancing as the demand for a particular application fluctuates.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Choice of Servers, Tools, and Components The J2EE standard and J2EE brand are central to creating a marketplace for servers, tools, and components. The J2EE brand on a server product ensures the kind of ubiquity that’s fundamental to the goals of the J2EE platform. In addition, J2EE standards ensure a lively marketplace for tools and components. A range of server choices: Application development organizations can expect J2EE branded platforms from a variety of vendors, providing a range of choices in hardware platforms, operating systems, and server configurations. This ensures that businesses get a choice of servers appropriate to the strategic purpose of the applications they need. A range of server choices: Application development organizations can expect J2EE branded platforms from a variety of vendors, providing a range of choices in hardware platforms, operating systems, and server configurations. This ensures that businesses get a choice of servers appropriate to the strategic purpose of the applications they need. Designed for tool support Designed for tool support Both EJB and JSP components are designed to be manipulated by graphical development tools, and to allow automating many of the application development tasks traditionally requiring the ability to write and debug code.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Choice of Servers, Tools, and Components Both J2EE server providers and third-party tool developers can develop tools that conform to J2EE standards and support various application development tasks and styles. Application developers get a choice of tools to manipulate and assemble components, and individual team members may choose tools that suit their specific requirements best. Both J2EE server providers and third-party tool developers can develop tools that conform to J2EE standards and support various application development tasks and styles. Application developers get a choice of tools to manipulate and assemble components, and individual team members may choose tools that suit their specific requirements best. A marketplace for components Component-based design ensures that many types of behavior can be standardized, packaged, and reused by any J2EE application. Component vendors will provide a variety of off- the-shelf component solutions, including accounting beans, user interface templates, and even vertical market functionality of interest in specific industries. Application architects get a choice of standardized components to handle common or specialized tasks. A marketplace for components Component-based design ensures that many types of behavior can be standardized, packaged, and reused by any J2EE application. Component vendors will provide a variety of off- the-shelf component solutions, including accounting beans, user interface templates, and even vertical market functionality of interest in specific industries. Application architects get a choice of standardized components to handle common or specialized tasks.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Simplified, Unified Security Model The J2EE security model is designed to support single sign- on access to application services. Component developers can specify the security requirements of a component at the method level, to ensure that only users with appropriate permissions can access specific data operations. The J2EE security model is designed to support single sign- on access to application services. Component developers can specify the security requirements of a component at the method level, to ensure that only users with appropriate permissions can access specific data operations. While the EJB and Java Servlet APIs both provide mechanisms for building security checks into code, the basic mechanism for matching users with roles (groups of users having specific permissions) is performed entirely at application deployment time. This provides both greater flexibility and better security control. While the EJB and Java Servlet APIs both provide mechanisms for building security checks into code, the basic mechanism for matching users with roles (groups of users having specific permissions) is performed entirely at application deployment time. This provides both greater flexibility and better security control.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Summary Summary The challenge to IT professionals today is to efficiently develop and deploy distributed applications for use on both corporate intranets and over the Internet. Companies that can do this effectively will gain strategic advantage in the information economy. The challenge to IT professionals today is to efficiently develop and deploy distributed applications for use on both corporate intranets and over the Internet. Companies that can do this effectively will gain strategic advantage in the information economy. The Java 2 Platform, Enterprise Edition is a standard set of Java technologies that streamline the development, deployment, and management of enterprise applications. The J2EE platform is functionally complete in the sense that it is possible to develop a large class of enterprise applications using all the range of technologies that the java language can provide. The Java 2 Platform, Enterprise Edition is a standard set of Java technologies that streamline the development, deployment, and management of enterprise applications. The J2EE platform is functionally complete in the sense that it is possible to develop a large class of enterprise applications using all the range of technologies that the java language can provide.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business References & Resources SUN Microsystems Technology Evangelists Main Page. SUN Microsystems Technology Evangelists Main Page. The Java Language Reference. The Java Language Reference Max Goff is a Technology Evangelist for Sun Microsystems, specializing in various Java technology-related topics.

Nikolaos Korfiatis The Java 2 Enterprise Edition Platform Dept. of Management & Technology-Athens University of Economics and Business Java 2 Platform Enterprise Edition(J2EE) A Model for Enterprise Application Development Report from the Java Days Conference Athens,Greece 17/01/2002 Nikolaos Th. Korfiatis Undergraduate Student Department of Management Science and Technology Athens University of Economics and Business