EJB servers are transactional servers that allow developers to concentrate on
business logic. The EJB model implements two-phase commits, transaction
context propagation and distributed transaction, although it's up to the
vendors to decide which technique to use.
A transaction is formally defined as an "ACID" (atomic, consistent, isolated,
durable) unit of work. Atomic transactions are "all or nothing." They either
work or they don't they're never left incomplete. Consistent transactions
always leave the system in a consistent state. Isolated transactions execute
in a safe manner they won't fail if other transactions running on the same
server are failing. Durable transactionscan survive system failures once
they're completed and committed. For example, an online sale may involve the
following steps: Begin transaction.
Charge card sale amount.
Update sale databa... (more)
As architects and developers continue to design and implement Web Services in
distributed environments, they are faced with a versioning issue - namely,
how do you deprecate, evolve, and continue to use different versions of the
same service with multiple service consumers. This article explores the
implementation issues and identifies versioning patterns and strategies that
can be employed to resolve them. Practical code examples using Java API for
XML-based Web Services (JAX-WS) can be downloaded from the online version of
this article at http:soa.sys-con.com.
The versioning i... (more)
Web services facilitate application-to-application integration and
interoperability across different platforms. However, critics usually point
to an inefficient processing model and bandwidth requirements for developing
Web services. This is often cited as a reason why Web services cannot perform
and scale well in production environments. This session takes a detailed look
at performance and scalability issues around Web services in the real world,
as well as strategies that architects and developers can adopt to mitigate
such risks in these applications. Some analytical and mode... (more)
Sameer Tyagi, an enterprise architect, focuses on strategy, design, and implementation of large-scale enterprise applications. His publications include several books and periodicals on technology. He can be reached at http://sameertyagi.blogspot.com.
Sue Poremba
Scott Sellers
Anthony Franco
Daniel Morris
Wayne Walls
Niki Acosta
Jereme Hancock
Oren Michels
Marvin Wheeler
Douglas Kim
