What are the components of J2EE application?

A J2EE component is a self-contained functional
software unit that is assembled into a J2EE
application with its related classes and files and
communicates with other components. The J2EE
specification defines the following J2EE components:

Application clients and applets are client components.


Java Servlet and JavaServer PagesTM (JSPTM) technology
components are web components.

Enterprise JavaBeansTM (EJBTM) components (enterprise
beans) are business components.

Resource adapter components provided by EIS and tool
vendors.