The J2EE API Can be Summarized As Follows:

J2EE TECHONOLOGY CATEGORY            API (APPLICATION PROGRAMMING INTERFACE)

1. COMPONENT TECHNOLOGY                 JAVA SERVLET, JAVA SERVER PAGES,
                                                                          ENTERPRISE JAVA BEANS(EJB)

2. WEB SERVICES TECHNOLOGY              JAXP(Java API for XML Processing),
                                                                         JAXR(Java API for XML Registers),
                                                                         SARJ( SOAP(Simple Object Access Protocal) with
                                                                         Attachement API for Java),
                                                                         JAX-RPC(Java API for XML-based RPC),
                                                                         JAX-WS(Java API for XML- based Web Services).

3. OTHERS                                                      JDBC(Java Data Base Connectivity), JNDI(Java Namming 
                                                                         and Directory Interface), JMS(Java Messaging Service), 
                                                                         JCA(J2EE Connector Architecture), JTA(Java Transaction
                                                                         API), Java Mail , JAF(Java Beans Active Framework-
                                                                         used by Java Mail), JAAS(Java Authentication and
                                                                         Authorization Serviec), JMX(Java Management eXtensions)