JAVA EE basic concept( official definition)

1. On the conceptual level, a service is a software component provided through a network-accessible endpoint.

2. The business logic is the code that fulfills the purpose of the application.

3. System-level services, is such as transaction management and security authorization.

4. Java EE component, is such as an application client, another enterprise bean, or a web component) .

5. A Java servlet is a web component that responds to HTTP requests

6. The naming system determines the syntax that the name must follow. This syntax is sometimes called the naming systems naming convention.

7. The association of a name with an object is called a binding. A file name is bound to a file.

8. A context is a set of name-to-object bindings. Every context has an associated naming convention.

9. A naming system is a connected set of contexts of the same type (they have the same naming convention) and provides a common set of operations.A naming system provides a naming service to its customers for performing naming-related operations. A naming service is accessed through its own interface.

10. A namespace is the set of all possible names in a naming system.

11. Many naming services are extended with a directory service. A directory service associates names with objects and also associates such objects with attributes.

12. directory service = naming service + objects containing attributes

13. A directory object contains attributesthat describe the object that it represents.A directory object represents an object in a computing environment.

14. A directory is a connected set of directory objects. A directory service is a service that provides operations for creating, adding, removing, and modifying the attributes associated with objects in a directory. The service is accessed through its own interface.

15. RMI applications often comprise two separate programs, a server and a client. A typical server program creates some remote objects, makes references to these objects accessible, and waits for clients to invoke methods on these objects. A typical client program obtains a remote reference to one or more remote objects on a server and then invokes methods on them. RMI provides the mechanism by which the server and the client communicate and pass information back and forth. Such an application is sometimes referred to as a distributed object application.

16. Objects with methods that can be invoked across Java virtual machines are called remote objects.

17. The stub acts as the local representative, or proxy, for the remote object and basically is, to the client, the remote reference.


18. The compute engine is a remote object on the server that takes tasks from clients, runs the tasks, and returns any results.

19. Such an application, which has the ability to download code dynamically, is often called a behavior-based application
Web components can be Java servlets, web pages implemented with JavaServer Faces technology, web service endpoints, or JSP pages.

20. Web components are supported by the services of a runtime platform called a web container. A web container provides such services as request dispatching, security, concurrency, and lifecycle management. A web container also gives web components access to such APIs as naming, transactions, and email.

21. The configuration information can be specified using Java EE annotations or can be maintained in a text file in XML format called a web application deployment descriptor (DD)

22.