J2EE APIs

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J2EE APIs

The Java 2 Platform, Standard Edition (J2SE) SDK is required to run the J2EE SDK and provides core APIs for writing J2EE components, core development tools, and the Java virtual machine. The J2EE SDK provides the following APIs to be used in J2EE applications.

Enterprise JavaBeans Technology 2.0

An enterprise bean is a body of code with fields and methods to implement modules of business logic. You can think of an enterprise bean as a building block that can be used alone or with other enterprise beans to execute business logic on the J2EE server.

There are three kinds of enterprise beans: session beans, entity beans, and message-driven beans. Enterprise beans often interact with databases. One of the benefits of entity beans is that you do not have to write any SQL code or use the JDBC API directly to perform database access operations; the EJB container handles this for you. However, if you override the default container-managed persistence for any reason, you will need to use the JDBC API. Also, if you choose to have a session bean access the database, you have to use the JDBC API.

JDBC API 2.0

The JDBC API lets you invoke SQL commands from Java programming language methods. You use the JDBC API in an enterprise bean when you override the default container-managed persistence or have a session bean access the database. With container-managed persistence, the container handles database access operations, and your enterprise bean implementation contains no JDBC code or SQL commands. You can also use the JDBC API from a servlet or JSP page to access the database directly without going through an enterprise bean.

The JDBC API has two parts: an application-level interface used by the application components to access a database, and a service provider interface to attach a JDBC driver to the J2EE platform.

Java Servlet Technology 2.3

Java Servlet technology lets you define HTTP-specific servlet classes. A servlet class extends the capabilities of servers that host applications accessed by way of a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers.

JavaServer Pages Technology 1.2

JavaServer Pages technology lets you put snippets of servlet code directly into a text-based document. A JSP page is a text-based document that contains two types of text: static template data, which can be expressed in any text-based format such as HTML, WML, and XML, and JSP elements, which determine how the page constructs dynamic content.

Java Message Service 1.0

The JMS is a messaging standard that allows J2EE application components to create, send, receive, and read messages. It enables distributed communication that is loosely coupled, reliable, and asynchronous

Java Naming and Directory Interface 1.2

The JNDI provides naming and directory functionality. It provides applications with methods for performing standard directory operations, such as associating attributes with objects and searching for objects using their attributes. Using JNDI, a J2EE application can store and retrieve any type of named Java object.

Because JNDI is independent of any specific implementations, applications can use JNDI to access multiple naming and directory services, including existing naming and directory services such as LDAP, NDS, DNS, and NIS. This allows J2EE applications to coexist with legacy applications and systems.



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