Enterprise beans are the Java EE server side components that run inside the ejb container and encapsulate the business logic of an enterprise application.
To Enterprise Java Bean 3.0
Enterprise beans are the Java EE server side components that run inside the ejb container and encapsulate the business logic of an enterprise application. Enterprise applications are the software applications developed intended to use at large scale. These applications involve large number of data accessing concurrently by many users. Enterprise beans are used to perform various types of task like interacting with the client, maintaining session for the clients retrieving and holding data from the database and communicating with the server.
An EJB container is nothing but the program that runs on the server and implements the EJB specifications. EJB container provides special type of the environment suitable for running the enterprise components. The EJB container manages remote access to the bean, security, persistence, transactions, concurrency, and access to and pooling of resources. It hosts an enterprise bean in the same manner that the Java Web Server hosts a servlet or an HTML. An enterprise bean can?t perform functions outside of an EJB container.
Read more information at: