The J2EE platform enables applications to access systems that are outside of the application server. Applications connect to these systems through objects called resources. One of the responsibilities of an administrator is resource configuration. The J2EE platform enables access to external systems through the following APIs and components:
JDBC - A database management system (DBMS) provides facilities for storing, organizing, and retrieving data. Most business applications store data in relational databases, which applications access via the JDBC API. The information in databases is often described as persistent because it is saved on disk and exists after the application ends. The Application Server includes the Derby DBMS.
Messaging - Messaging is a method of communication between software components or applications. A messaging client sends messages to, and receives messages from, any other client. Applications access the messaging provider through the Java Messaging Service (JMS) API. The Application Server includes a JMS provider.
Connector - The J2EE Connector architecture enables integration between J2EE applications and existing Enterprise Information Systems (EIS). An application accesses an EIS through a portable J2EE component called a connector or resource adapter.
Server Administration -The lower right-hand corner of Figure 1-1 shows some of the tasks performed by the administrator of the Application Server. For example, an administrator deploys (installs) applications and monitors the server’s performance. These tasks are performed with the administration tools provided by the Application Server.