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Reference Implementation Software
The J2EE SDK is a non-commercial operational definition of the J2EE platform and specification made freely available by Sun Microsystems for demonstrations, prototyping, and educational uses. It comes with the J2EE application server, web server, relational database, J2EE APIs, and complete set of development and deployment tools. You can download the J2EE SDK from the web:
http://java.sun.com/j2ee/download.html#sdk
- Product providers use the J2EE SDK to determine what their implementations must do under a given set of application conditions, and to run the J2EE Compatibility Test Suite to test that their J2EE products fully comply with the specification.
- Application component developers run their J2EE applications on the J2EE SDK to verify the applications are fully portable across all J2EE products and tools.
Web Server
The web server provides services to one or more web containers. For example, a web container typically relies on a web server to provide HTTP message handling. A J2EE implementation is not required to support a particular type of web server, which means the web server supported by different J2EE products can vary.
Database Access
The relational database provides persistent storage for application data. A J2EE implementation is not required to support a particular type of database which means the database supported by different J2EE products can vary. See the Release Notes included with the J2EE SDK download for a list of the databases currently supported by the reference implementation.
J2EE APIs
The Java 2 Platform, Standard Edition (J2SETM) 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 as described in Business Components. You do not have to write any SQL code or use the JDBCTM API directly to perform database access operations with an entity bean. The EJB container handles this for you. However, if you override the default container-managed persistence for any reason, you will need t use the JDBC API. Also, if you choose to have a session bean access the database, you have to use the JDBC API.
JDBCTM 2.0 API
The JDBC API lets you invoke SQL commands from Java programing 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, database access operations are handled by the container 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 (JSP) Technology 1.2
JSP 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 that determine how the page constructs dynamic content.
Java Message Service (JMS) 1.0
The JMS API 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. For more information on JMS see the online Java Message Service Tutorial:
http://java.sun.com/products/jms/tutorial/index.htmlJava Transaction API (JTA) 1.0
The JTA API provides a standard demarcation interface for demarcating transactions. The J2EE architecture provides a default auto commit to handle transaction commits and roll backs. An auto commit means any other applications viewing data will see the updated data after each database read or write operation. However, if your application performs two separate database access operations that depend on each other, you will want to use the JTA API to demarcate where the entire transaction including both operations begins, rolls back, and commits.
JavaMailTM Technology 1.2
Many Internet applications need to send email notifications so the J2EE platform includes the JavaMail API with a JavaMail service provider that application components can use to send Internet mail. The JavaMail API has two parts: an application-level interface used by the application components to send mail, and a service provider interface.
JavaBeans Activation Framework 1.0
The JavaBeans Activation Framework is included because JavaMail uses it. It provides standard services to determine the type of an arbitrary piece of data, encapsulate access to it, discover the operations available on it, and create the appropriate JavaBean component to perform those operations.
Java API for XML (JAXP) 1.1
XML is a language for representing and describing text-based data so the data can be read and handled by any program or tool that uses XML APIs. Programs and tools can generate XML files that other programs and tools can read and handle.
For example, a J2EE application can use XML to produce reports, and different companies that receive the reports can handle the data in a way that best suits their needs. One company might put the XML data through a program to translate the XML to HTML so it can post the reports to the web, another company might put the XML data through a tool to create a marketing presentation, and yet another company might read the XML data into its J2EE application for processing.
J2EE Connector API 1.0
The Connector API is used by J2EE tools vendors and system integrators to create resource adapters that support access to enterprise information systems that can be plugged into any J2EE product. A resource adapter is a software component that allows J2EE application components to access and interact with the underlying resource manager. Because a resource adapter is specific to its resource manager, there is typically a different resource adapter for each type of database or EIS.
Java Authentication and Authorization Service (JAAS) 1.0
The Java Authentication and Authorization Service (JAAS) provides a way for a J2EE application to authenticate and authorize a specific user or group of users to run it.
JAAS is a Java programing language version of the standard Pluggable Authentication Module (PAM) framework that extends the Java 2 platform security architecture to support user-based authorization.
Tools
The J2EE reference implementation provides an application deployment tool and an array of scripts for assembling, verifying, and deploying J2EE applications and managing your development and production environments. See J2EETM SDK Tools for a discussion of the tools.
Application Deployment Tool
The J2EE reference implementation provides an application deployment tool for assembling, verifying, and deploying J2EE applications. It comes in two versions: command-line and GUI.
The GUI tool includes wizards for
- Packaging, configuring, and deploying J2EE applications
- Packaging and configuring enterprise beans
- Packaging and configuring web components
- Packaging and configuring application clients
- Packaging and configuring resource adaptors
In addition, configuration information can be set for each component and module type in the tabbed inspector panels.
Scripts
Table 1 lists the scripts included with the J2EE reference implementation that let you perform operations from the command line.
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