Java Beans

• Java Beans are software component model. it is general purpose component model. java bean is a reusable software component that can be visually manipulated in builder tools.
• The primary goal of a Java Bean is Write Once Run Anywhere.
• Java Beans should adhere to portability, reusability and introperability.

Introduction of EJB

• Enterprise Java Beans are software component models, their purpose is to build/ support enterprise specific problems.
• EJB - is a reusable server side software component.

(Figure: Component Model Architecture)

(What is Component? Software Component is a software package, or a web service, or a web resource, or module that encapsulates a set of related functions or data.)

• EJB facilitates the development of distributed java applications, providing an object oriented transactional environment for building distributed, multi - tier enterprise components.
• An EJB is a remote object, which needs the services of an EJB container in order to execute.
• EJB is an essential part of J2EE platform.
• J2EE platform have component based architecture to provide multi-tiered, distributed and highly transactional features to enterprise level applications.
• EJB provides an architecture to develop and deploy component based enterprise applications considering robustness, high scalability and high performance.  
• An EJB application can be deployed on any of the application server compliant with J2EE 1.3 standard specification.