Technologists building the Spring Framework for Java application development are mapping out improvements to the platform as well as determining which versions of Java will no longer be supported by upgrades to the framework.

Version 2.5 of the open-source framework for is set for release on November 19. Key improvements include greater use of annotations and metadata. The metadata is information that supplements Java code by providing extra information that can tell the Spring container how to process a class or a method.

"Many of the new features in Spring 2.5 concern really making extensive use of the new language features in Java 5 and also Java 6," said Rod Johnson, founder of the framework and CEO of Interface21. Java 5 features, for example, more options to add metadata inside Java source code, he said.

With version 2.5, greater use of annotations is offered for configurations. Also, developers with version 2.5 can define components using XML outside Java or define components using source-level metadata, Johnson said. By maintaining metadata outside of Java, developers can change the configuration of an application without recompiling Java code.

Spring 2.5 drops support for J2EE (Java 2 Enterprise Edition) 1.3 version of Java, leaving support for J2EE 1.4 as well as Java standard editions 5 and Java 6.

"Basically, we found we didn't have many users left on 1.3, and, of course, they could continue to use Spring 2," Johnson said.

With the planned Spring 3.0 release, support probably will be dropped for J2EE 1.4. But there is no timeframe yet for releasing of Spring 3.0 and Spring's developers take backward compatibility and user migration seriously, Johnson stressed. Version 3.0 will not be released until the great majority of Spring users want to move off of J2EE 1.4, he said.

The decision to drop support for some older Java versions did not upset prominent Java developer Rick Ross, founder of the Javalobby developer community and DZone, which oversees Javalobby. Ross, a user of Spring, said he was not clear why some firms continue to deploy on "seriously obsolete versions" of Java, other than to be conservative.

"Rod Johnson knows who his users are and I know he wouldn't leave them up a creek without a paddle," Ross said.

As part of its Java 6-based improvements, Spring 2.5 offers improved JDBC (Java Database Connectivity) support. "There is better exception handling [for errors] and Spring can take advantage of those new capabilities," Johnson said.

Spring 2.5 also offers additional XML namespaces, for extending an XML document. Another feature is improved integration with IBM's WebSphere 6.1 application server. Improvements in Spring MVC (Model View Controller), meanwhile, make it easier to configure. MVC deals with HTTP requests.