Best practice for distributing/releasing J2EE applications.

Question

Hi All,
We are developing a J2EE application and would like some information on the best
practices to be followed for distributing/releasing J2EE applications, in general.
In particular, the dilemma we have is centered around the generation of stub, skeleton
and additional classes for the application.
Most App. Servers can generate the required classes while deploying the EJBs in the
application i.e. at install time. While some ( BEA Weblogic and IBM Websphere are
two that we are aware of ) allow these classes to be generated before the installation
time and the .ear file containing the additional classes is the one that is uploaded.
For instance, say we have assembled the application "myapp.ear" . There are two ways
in which the classes can be generated. The first is using 'ejbc' ( assume we are
using BEA Weblogic ), which generates the stub, skeleton and additional classes for
the application and returns the file, say, "Deployable_myapp.ear" containing all
the necessary classes and files. This file is the one that is then installed. The
other option is to install the file "myapp.ear" and let the Weblogic App. server
itself, generate the required classes at the installation time.
If the first way, of 'pre-generating' the stubs is followed, does it require us to
separately generate the stubs for each versions of the App. Server that we support
? i.e. if we generate a deployable file having the required classes using the 'ejbc'
of Weblogic Ver5.1, can the same file be installed on Weblogic Ver6.1 or do we
have to generate a separate file?
If the second method, of 'install-time-generation' of stubs is used, what is the
nature/magnitude of the risk that we are taking in terms of the failure of the installation
Any links to useful resources as well as comments/suggestions will be appreciated.
TIA
Regards,
Aasif

Answer 1

Its much easier to distribute schema/data from an older version to a newer one than the other way around. Nearly all SQL Server deployment features supports database version upgrade, and these include the "Copy Database" wizard, BACKUP/RESTORE,
detach/attach, script generation, Microsoft Sync framework, and a few others.
EVEN if you just want to distribute schemas, you may want to distribute the entire database, and then truncate the tables to purge data.
Backing up and restoring your database is by far the most RELIABLE method of distributing it, but it may not be pratical in some cases because you'll need to generate a new backup every time a schema change occurs, but not if you already have an automated
backup/maintenance routine in your environment.
As an alternative, you can Copy Database functionality in SSMS, although it may present itself unstable in some situations, specially if you are distributing across multiple subnets and/or domains. It will also require you to purge data if/when applicable.
Another option is to detach your database, copy its files, and then attach them in both the source and destination instances. It will generate downtime for your detached databases, so there are better methods for distribution available.
And then there is the previously mentioned method of generating scripts for schema, and then using an INSERT statement or the import data wizard available in SSMS (which is very practical and implements a SSIS package internally that can be saved for repeated
executions). Works fine, not as practical as the other options, but is the best way for distributing databases when their version is being downgraded.
With all this said, there is no "best practice" for this. There are multiple features, each offering their own advantages and downfalls which allow them to align to different business requirements.