SAP Web AS for Java Applications  

J2EE Standard

The SAP J2EE Engine is an integral component of the SAP Web Application Server and implements the J2EE standard. This J2EE standard has been defined by the Java Community according to the rules of the Java Community Process and is copyright protected by Sun Microsystems. Since November 2002 SAP has been a member of the Executive Committee of the Java Community.

The SAP J2EE Engine in the SAP Web Application Server SAP fulfils more than just the J2EE standard - its functions stretch far beyond the standard. To make the conversion of larger software projects easier, SAP has equipped the J2EE Engine with the following central developments:

·        SAP Java Connector (connects ABAP and JAVA)

·        Java Persistence (implementation of a database-independent persistence layer)

·        Web Dynpro (front-end technology with far more functions than JSP and Servlets)

Purpose

With the SAP Web Application Server SAP delivers a homogenous infrastructure for ABAP-based applications as well as for J2EE-based applications. All existing business objects and interfaces can be used the same both in the Java and ABAP environments.

Implementation Considerations

Prerequisites

To be able to understand the documentation, users should be familiar with:

·        Basic understanding of Web technologies (protocols, Web services, etc.)

·        Object-oriented programming

·        Java

·        Eclipse

·        Model View Controller (MVC) principles

Documentation

The documentation is divided into the following manuals:

Architecture Manual

Development Manual

Reference Manual

You can find the complete documentation for the SAP Web Application Server in the SAP Library provided in the standard delivery.

System Variants

J2EE technology can be implemented in the following system variants:

·        SAP Web Application Server ABAP + Java System

·        SAP Web Application Server Java System

For more information on installation see Installation Information.

Features

The SAP J2EE Engine supports component-based enterprise technologies and enables the fast development and deployment of secure, scalable, and manageable applications. The portability of applications is guaranteed by a large number of supported operating systems and database platforms. The J2EE Engine complies with both JMX 1.3 and with the Java 2 Enterprise Edition (J2EE) and implements Enterprise JavaBeans, Servlets, JSPs, JNDI, JMS and Java Mail in accordance with the specified standards.

The SAP J2EE Engine offers:

·        Scalability – fast response times at peak usage

·        Availability and reliability – continuous access to the entire system, 24 hours a day.

·        Support of current security standards (encryption and authentication)

·        Caching, multi-threading and multi-processing functions, enabling requests to be optimally processed at peak usage times

·        Dynamic load balancing which reduces response times and improves performance

·        Data replication to enable perfect recovery of crashed systems or systems with errors.

·        Clustering of Web pages and components to enable largest possible scalability and availability.

·        Configuration and administration of the system by remote management of the cluster nodes and applications.

·        Recording of logs at system and application level, classified by importance.

·        Continuous monitoring of performance of the cluster nodes and modules of the SAP J2EE Engine.

Load Balancing

The load balancing system of the SAP J2EE Engine distributes client requests evenly across the server processes of the cluster. In this way the whole capacity of each server process can be used to an optimum. The requests are forwarded for processing to the individual server processes. For more information see the Architecture Manual under Load Balancing of the SAP Web AS for J2EE Applications.

Failover

One of the most important capabilities of the SAP J2EE Engine is the failover function. There are several failover mechanisms:

The simple failover mechanism is used when a server breaks down. The dispatcher redirects client requests to another server process and this ensures minimum delay. Failover at session level is intercepted by the persistence layer of the SAP J2EE Engine. This is achieved by replicating session data synchronously to other specified server processes. For more information see High Availability and Failover.

Central Services

For the J2EE Engine central services are the basis for communication and synchronization. For more information see the Architecture guide under J2EE Cluster Architecture ® Central Services

Compliance with Java 2 Enterprise Edition

The SAP J2EE Engine supports the industry standard Java 2 Platform Enterprise Edition and therefore has a broad base of security and development standards. On this base you can develop applications, which are transferable and independent of the manufacturer. The SAP J2EE Engine supports the following J2EE components and interfaces:

..

·        Enterprise JavaBeans
All EJB types contained in the EJB 1.1 and EJB 2.0 specification:

¡        Stateful and stateless session beans

¡        Entity Beans

¡        Message-driven Beans

·        Java Server Pages (JSP)

·        Java Servlets

·        Java Transaction API (JTA)

·        JDBC 

·        Java Naming and Directory Interface (JNDI)

·        Java Mail

·        Java Message Service (JMS) 

·        Java API for XML Processing (JAXP)

·        Compliance with Java Security Specifications

·        Java Cryptography Architecture (JCA)

·        Java Cryptography Extension (JCA)

·        Improved Container-Managed Persistence (EJB CMP)

·        Query Language (EJB QL)

·        Connector Architecture