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IBM Software Group
J2EE Container Services Overview
© 2007 IBM Corporation
4.1.0.3
Unit objectives
After completing this unit, you should be able to:
 Describe the container services provided by J2EE
 Discuss J2EE interoperability
 List the J2EE platform roles
 Discuss the J2EE implementation
2
J2EE Standard Services – Overview (1 of 2)
 J2EE provides standard services to facilitate interaction with different
technologies
This also insulates the developer from the actual implementation of
the service
 Two services previously in J2EE now in J2SE in version 1.4:
JDBC (relational database connectivity)
JNDI (Java Naming and Directory Interface)
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J2EE Standard Services – Overview (2 of 2)
 The standard services provided in J2EE include the following:
Hypertext Transfer Protocol (HTTP)
Remote Method Invocation/Internet Inter-ORB Protocol (RMI-IIOP)
Java Interface Definition Language (Java IDL)
Java Transaction API (JTA)
Java Message Service (JMS)
JavaMail
JavaBeans Activation Framework (JAF)
Java API for XML Parsing (JAXP)
Web Services (including JAX-RPC and SAAJ)
J2EE Connector Architecture (JCA)
Java Authentication and Authorization Service (JAAS)
Java Authorization Service Provider Contract for Containers (JACC)
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J2SE Standard Services - JNDI
 Java Naming and Directory Interface
Standard Extension
JNDI provides directory and naming
functionality
The API is independent of the
directory implementation
JNDI enables applications to discover
and retrieve objects of any type
JNDI is used to register EJBs and to
access server-provided objects
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J2SE Standard Services - JDBC
 JDBC is an API that provides vendorindependent connectivity to a variety of
relational databases
 JDBC functionality provides basic
connectivity and core database-related
classes
 The Standard Extension provides
additional functionality
The Java Naming and Directory
Interface (JNDI) can be used to
manage data sources and
connections
Connection pooling can be
provided by database vendors to
enhance performance, particularly
for server applications
Support for distributed
transactions, including support for
the standard two-phase commit
protocol used by the Java
Transaction API (JTA)
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J2EE Standard Services - Communications
 Hypertext Transfer Protocol
The HTTP client-side API is defined
by the java.net package
The server-side API is defined by the
Servlet and JSP interfaces
The client- and server-side APIs also
support HTTP over secure sockets
(HTTPS)
 RMI-IIOP
Allows RMI-style programming
independent of protocol
Implementation supports both the
RMI protocol (JRMP) and CORBA
IIOP
 Java IDL
Allows J2EE components to invoke
external CORBA objects using IIOP,
which may be written in any language
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J2EE Standard Services - JTA
 Java Transaction API Standard
Extension
JTA specifies interfaces
between a transaction manager
and the parties involved in a
distributed transaction system
 The application, the resource
manager, and the application server
JTA is implementation-neutral
For application developers, the
UserTransaction interface is
the key
Application developers normally
want to use container-managed
transaction demarcation,
instead of using JTA
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J2EE Standard Services - Messaging
 Java Messaging Service Standard Extension
The Java Message Service is a standard,
vendor-neutral API used to access
enterprise message systems
Analogous to JDBC for databases
Allows for the delivery of asynchronous
messages in an application
 The JMS client sending the message does not have
to wait until the message has been processed
 JavaMail Standard Extension and JAF
JavaMail is used to add e-mail capability
to applications
Includes classes which encapsulate
common mail functions and protocols
Uses the JavaBeans Activation
Framework to encapsulate message data
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J2EE Standard Services - JAXP
 Java API for XML Parsing (JAXP)
JAXP enables applications to
parse and transform XML
documents
 Independent of XML processor
implementation
JAXP includes industry standard
components
 DOM (Document Object Model)
 SAX (Simple API for XML Processing)
 XSLT (XML Style Language
Transformations)
JAXP adds additional functionality
beyond these standards
 Java API for XML – Remote Procedure
Call (JAX-RPC)
Enables Java applications
incorporating XML-based RPC
functionality according to the
SOAP (Simple Object Access
Protocol) 1.1 specification
 Java API for XML Registries (JAX-R)
APIs to access UDDI Registry
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J2EE Standard Services - Web Services
 Web Services now part of J2EE 1.4
JAX-RPC 1.1
JAX-R
Web Services for J2EE specification (JSR 109)
 Standard deployment model of Web Services application
within a J2EE Application Server
WS-I Basic Profile 1.0
 Guidelines for interoperability in a heterogeneous
environment
SAAJ 1.1 – SOAP with attachments API for Java
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J2EE Standard Services - Connectors
 J2EE Connector Architecture (JCA)
Allows resource adapters that
support access to Enterprise
Information Systems (EIS) to be
plugged into J2EE products
Defines a connection
management contract between
a J2EE server and a resource
adapter to allow connection
pooling to EIS systems
Defines a transaction
management contract between
the transaction manager and an
EIS that supports transactional
access
 Also supports transactions that are
managed entirely by an EIS
Defines a security contract that
enables secure access to an
EIS
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J2EE Standard Services - JAAS
 Java Authentication and Authorization Service
(JAAS)
JAAS can be used for two purposes:
 Authentication of users, to reliably and securely
determine who is currently executing Java code,
regardless of how the code is running
 Authorization of users to ensure they have the
permissions required to do the actions performed
JAAS authentication is pluggable
 Java applications using JAAS remain independent from
underlying authentication technologies
JAAS authorization extends the existing Java
security architecture
 Access control can be based not just
on what code is running, but also on
who is running it
Java Authorization Service Provider Contract
for Containers (JACC)
 Allows custom authorization service providers to be
plugged into the Application Server
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J2EE Interoperability
 The J2EE platform includes interoperability requirements
J2EE may be used to integrate systems
 Applications written in different languages, like C++ or Visual Basic
 Applications running on different platforms, such as PCs or UNIX
workstations
 Stand-alone Java-based applications that are not directly supported by
J2EE
The interoperability requirements of J2EE make this
possible
 J2EE applications can connect to legacy systems using CORBA or
low-level socket interfaces
 J2EE applications can connect to other J2EE applications across
multiple J2EE products
Interoperability is achieved through the use of standard
protocols for communication and data transfer
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J2EE Platform Roles
 J2EE defines the following roles
J2EE product provider
 Implements a J2EE product that provides containers, APIs,
and other features
Application component provider
 Produces application building blocks (HTML documents,
EJBs, JSPs, and so forth)
 In many cases this role will be further subdivided
Application assembler
 Takes components developed by component providers and
assembles them into complete a J2EE application
Deployer
 Deploys, configures, and runs EJBs and Web applications
System administrator
 Configures and administers the infrastructure
Tool provider
 Provides application component development and packaging
tools
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J2EE Implementation
 The J2EE Compatibility Test Suite
Includes over 15000 tests for J2EE 1.4
Tests a candidate platform for J2EE compatibility
 Checks that all the necessary operations (for example, in required
APIs) are possible
 Checks that the behavior of the APIs meets the specification
 Checks end-to-end compatibility by performing operations on J2EE
components and back-end systems and checking the results
Ensures portability between platforms
 The J2EE Reference Implementation
Provides an operational definition of the J2EE platform
 The purpose is to validate the specification and act as a reference for
J2EE platform providers
Can be used by developers to confirm portability
Included as a binary with the J2EE Software Development
Kit (free for development and testing)
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Checkpoint
1. What do J2EE standard services offer?
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Checkpoint solutions
1. A standardized way of accessing services that enterprise
application require.
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Unit summary
Having completed this unit, you should be able to:
 Describe the container services provided by J2EE
 Discuss J2EE interoperability
 List the J2EE platform roles
 Discuss the J2EE implementation
19