Understand basic J2EE concepts

Currently, the Java 2 platform has three versions. These are the micro version of Java 2 platform (Java 2 platform Micro Edition, j2_based) applicable to small devices and smart cards) java 2 platform Standard Edition (Java 2 platform Standard Edition, j2se) for desktop systems and server application CreationProgramAnd Java 2 Platform Enterprise Edition (Java 2 Platform Enterprise Edition, J2EE ).
J2EE is an architecture that uses the Java 2 platform to simplify the development, deployment, and management of enterprise solutions. The foundation of J2EE technology is the Standard Edition of the core Java platform or Java 2 platform. J2EE not only consolidates many advantages of the Standard Edition, for example, the features of "writing once and running anywhere", jdbc api for convenient database access, and the technology of CORBA, as well as the security mode that can protect data in Internet applications, etc, it also provides comprehensive support for EJB (Enterprise JavaBeans), Java Servlets APIs, JSP (Java Server Pages), and XML technologies. The ultimate goal is to become an architecture that can greatly shorten the time to market for enterprise developers.
The J2EE architecture provides an intermediate layer integration framework to meet the needs of applications that require high availability, high reliability, and scalability without too much cost. By providing a unified development platform, J2EE reduces the cost and complexity of developing multi-tier applications. It also provides strong support for existing application integration and fully supports Enterprise JavaBeans, A good wizard supports packaging and deploying applications, adding directory support, enhancing the security mechanism and improving performance.