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J2EE APIs 35
Java Transaction API (JTA) to demarcate where the entire transaction, including both
operations, begins, rolls back, and commits.
To facilitate transactions, J2EE has two APIs: JTA and Java Transaction Service (JTS).
JTA is a high-level transaction interface that your applications use to control transactions.
JTS is a set of low-level transaction interfaces that EJBs use behind the scenes (your client
code does not directly interact with JTS). One of the main advantages of EJBs is that the
EJB container manages transactions declaratively, with no transaction logic required in
the code.
JavaMail 1.2
The J2EE platform includes the JavaMail API with a JavaMail service provider that
application components can use to send Internet mail. J2EE includes JavaMail to
support applications such as e-commerce websites for its ability to send order
confirmations and other user feedback. 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 (JAF) 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 JavaBeans component to perform those
operations. JavaMail uses JAF.
Java API for XML 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 the XML API. For example, a J2EE
application can use JAXP 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 it on the
web and another company might read the XML data into its J2EE application for
processing.
J2EE Connector API 1.0
J2EE supports integration with existing enterprise information systems (EIS) through
connectors called
resource adapters . A resource adapter is a vendor-specific bridge that
links an existing system to J2EE.
J2EE tools vendors and system integrators use the J2EE Connector API (JCA) to create
resource adapters that support access to legacy systems that can be plugged into any J2EE
product. A resource adapter is a software component that lets J2EE application
components access and interact with the underlying resource manager. Because a resource
adapter is specific for a resource manager, there is typically a different resource adapter for
each type of database or EIS.
The JCA architecture defines a set of contracts that a resource adapter must support to
plug into a J2EE product; for example, transactions, security, and resource management.