22-05-2012, 04:29 PM
Enterprise Java Beans
enterprise java beans.ppt (Size: 353.5 KB / Downloads: 31)
Application Servers
In the late 1980s and though the mid 1990s a number of corporations (Broad vision, Netscape…) marketed a class of server products to enable the creation of highly scaleable applications.
Used proprietary interfaces to OLTP (On-line Transaction Processing) tools like BEA Tuxedo and IBM TXSeries
APIs are not standardized
Applications developed on one application server were not portable to another application server
every application ended up being custom written
once one vendor‘s application server was installed, you were stuck with it and at the mercy of that vendor
vendor’s did a good job of convincing you how easy it was to use their product but were really trying to sell customization and consulting services
J2EE Industry Acceptance
To be successful J2EE must have wide industry acceptance
APIs would be useless if infrastructure vendors don’t implement support for the J2EE APIs
Sun made alliances with many Industry leaders to insure the success of J2EE
Transaction Management
IBM, Compaq/Tandem, BEA Systems
Persistence Management
Oracle, Sybase, Informix
Directory Services
HP, Netscape, IBM
RMI/IIOP
Allows the creation of remote interfaces for distributed computing
default protocol (JRMP, Java Remote Method Protocol) is proprietary, based on Java’s serialization APIs
RMI-IIOP a JDK 1.3 extension of RMI that allows the use of IIOP (Internet Inter ORB Protocol) for RMI communication. J2EE Spec requires this as the standard protocol for communications between the different tiers of the J2EE architecture.
What is Enterprise Java Beans
Defines a model for the development and deployment of reusable Java server components
Components are pre-developed pieces of applications code that can be assembled into working application systems
The EJB Architecture logically extends the Java Beans component model to support server components
Server components run in an application server
A Java application server provides an optimized execution environment for server-side Java application components
by combining traditional OLTP (On-line Transaction Processing) technologies with a Java application server delivers a high performance, highly scalable, robust execution environment specifically suited to support Internet enabled application systems