IBM WebSphere Application Server supports a wide variety of
technologies for building powerful enterprise applications. As
technology advances, particularly in the area of Java components,
new Application Server product versions advance to support and
extend the most contemporary open specification levels.
If your existing applications currently support different specification
levels than are supported by this version of the product, it
is likely you will need to update at least a few
aspects of the applications to comply with the new specifications.
In many cases, IBM extends the specification levels that are currently
supported by the product to provide additional
features and customization options. If your existing applications
use extensions from earlier product versions, mandatory
or optional migration could be necessary to utilize the same
kinds of extensions in the current version.
From Version 3.0x to
Version 4.0,
the main migration areas
concern the IBM extensions and the JDK. In contrast, migrating
from Version 2.0x requires updating applications with respect
to the open specifications, such as the Java Servlet API.
The table summarizes potential migration areas. See the
Related information below for instructions pertaining to each area.
Version 2.0x supported the Servlet 2.0 Specification.
JSP files
JSP .91 Specification
Yes
Yes
JSP 0.91 is not supported in Version 4.0.
JSP files
JSP 1.0 Specification
Yes*
Yes
* Many JSP 1.0 applications will run unchanged in Version 4.0; however, some changes may be required or
recommended.
Version 2.0x only supported the JSP .91 Specification.
JSP files
JSP 1.1
Specification
No
not applicable
Version 2.0x only supported the JSP .91 Specification.
XML
XML 2.0.x supported
Yes
Yes
See article 3.3.4 for migration requirements.
JDBC and IBM database connection support APIs
JDBC 2.0; connection pooling model
Yes
Yes
V2.0x supported JDBC 1.0 and a connection manager model.
If still using Connection Manager,
you must
switch to connection pooling.
Do not forget to switch to supported JDBC 2.0 drivers.
User profiles
IBM user profile APIs
No
Yes
Need to migrate from V2.0x deprecated
classes for use with V4.0.
Sessions
IBM session support APIs
No
Yes
Need to migrate from V2.0x deprecated
classes,
changes to clustering, URL encoding
for use with V4.0.
Security
IBM security support
No
No
No action required.
However, unlike previous versions,
Version 4.0 does not protect URIs
served by an external Web server.
Version 4.0 continues to protect URIs
(including URIs for HTML files) that are served by the application server.
Transactions
Java 1.2 transactions support
Yes
Yes
Version 3.0x provided proprietary IBM packages to simulate
Java 1.2 functionality. Version 2.0x did not provide any
support.
Migrate to Version 4.0 if your applications require this
kind of support.
XML configuration
XMLConfig tool
Yes
Yes
The XML Configuration Management Tool (XMLConfig) was
introduced in Version 3.02.
The DTD and many of the interfaces have
changed in Version 4.0.
XMLConfig is not supported
in Version 4.0 Advanced Single Server Edition.
WebSphere Control Program
WSCP
Yes
not applicable
The WebSphere Control Program (WSCP) was introduced in Version 3.5.
WSCP is not supported
in Version 4.0 Advanced Single Server Edition.