Enterprise Java Beans Java for the Enterprise Server-based platform for Enterprise Applications Designed for “medium-to-large scale business, enterprise-wide systems, multi-tier environment, distributed data sources, and serious users of middleware applications.”

Java Enterprise API’s Enterprise Java Beans: The Enterprise JavaBeans specification defines an API that will make it easy for developers to create, deploy and manage cross-platform, component-based enterprise applications that work within the framework of the systems currently in use.

JavaServer Pages combines easy-to-use server-side tags with the power of JavaBeans TM components to provide a solution that cleanly separates the presentation of dynamic content from the generation of that content. Neutral to development platforms and Web servers, it's a Write Once, Run Anywhere TM solution. The Java Servlet API provides a uniform, industry-supported interface for extending a web server with cross-platform and cross-server components written in the Java Programming Language. JNDI: Provides uniform, industry-standard, seamless connectivity from the Java platform to business information assets, thus allowing developers to deliver Java applications with unified access to multiple naming and directory services across the enterprise.

JavaIDL: Provides interoperability with CORBA, the industry standard for heterogeneous computing. Java IDL includes an IDL-to-Java compiler and a lightweight ORB that supports IIOP. JDBC: Included in JDK 1.1. Provides programmers with a uniform interface to a wide range of relational databases, and provides a common base on which higher-level tools and interfaces can be built. RMI: Included in JDK 1.1. Designed for creating Java objects whose methods can be invoked from another virtual machine. Object Serialization allows programs to serialize objects into a stream of bytes that can be later used to build equivalent objects. The Java Message Service specification provides developers with a standard Java API for enterprise messaging services such as reliable queuing, publish and subscribe communication and various aspects of push/pull technologies.

Java Transaction API (JTA) defines a high-level transaction management specification intended for resource managers and transactional applications in distributed transaction systems. The Java Transaction Service (JTS) API technology ensures interoperability with sophisticated transaction resources such as transactional application programs, resource managers, transaction processing monitors and transaction managers. Since these components are provided by different vendors, JTS provides open, standard access to these transaction resources. RMI-IIOP provides developers an implementation of the Java RMI API over the Object Management Group's industry-standard Internet Inter-Orb Protocol (IIOP). With it, developers can write remote interfaces between clients and servers, and implement them just using Java technology and the Java RMI APIs.

EJB and Distributed Objects Distributed, Mutitier development integral part of enterprise framework Standard way to write systems that do not lock into proprietary toolsets

Example Oracle Network Computing ArchitectureOracle Transaction management and data access API’s are Oracle Specific Not portable (porting to Sybase?) In future (Oracle 8.1), server components with ejb and jdbc, via CORBA/IIOP, that are interchangeable among ejb compliant servers

EJB Model Purpose: Standardized Middle-Tier Server Development Standard Component Architecture Rapid Application Development (isolated from low-level details) Support for multiple vendor tools Extendable to existing server products CORBA

Containers: Execution Environment (server) conform to EJB specification Standard Java Beans are client side components. Cannot be accessed and manipulated by other components at runtime. Entity Beans: Persistent objects Session Beans: Transient Default to RMI CORBA Compliant (Glue) Clients in any CORBA compliant language

Web Applications

IBM e-business Frameworke-business

System Overview Three Tier Clients: Presentation and requests for Information through browser/applet Web Application Server with business logic and process that control access to data Data Servers with Data Storage and Transaction Services

Integration

Clients