Sun is offering on Thursday its open-source Sun GlassFish Enterprise Server version 3 Prelude, a Web application server based on a modular OSGi architecture with capabilities from the planned Java Platform EE (Enterprise Edition) 6 release.

The application server, which will be supported by Sun, is geared to Web-tier production environments. It will be the basis for the planned GlassFish Enterprise Server v3, also based on OSGi and Java EE 6 and due next year.

"Glassfish v3 Prelude is our OSGI microkernel application server," said Paul Hinz, director of product management for Java enterprise systems at Sun.

"OSGi allows you to have an architecture where you have a kernel that allows pluggable modules and each module can do different things," such as one that processes Ruby code and another to process Enterprise JavaBeans (EJB), Hinz said.

OSGI provides a strategy to make application servers simpler and faster, said analyst Jonathan Eunice, principal IT advisor at Illuminata. It offers a smaller memory footprint, he said.

"The idea is you don't load modules you don't need," Eunice said.

Java EE 6 preview features include JavaServer Faces 2.0, for dragging and dropping of user interface components. JAX-RS 1.0 is supported for building RESTful Web services.

The Cometd technology offered in the application server enables data to be pushed out to a browser, which is beneficial for rich Internet applications, Sun said.

Other features in v3 Prelude include ease of installation and management and enhanced JRuby support, Sun said. JRuby is a version of the Ruby language that runs on the Java Virtual Machine. JRuby can be used in a native format, for quicker testing and deployment. Users also can run language platforms, such as Java, Groovy on Grails, and JRuby on Rails.

Sun is eyeing users of the Apache Tomcat servlet container as potential users of Glassfish v3 Prelude, saying Prelude is lightweight, easy to use, open source, and has easy administration. Applications on Tomcat can be placed on the Glassfish software with no modifications, Hinz said.

The administration console in v3 Prelude offers point-and-click configuration and the ability to install components from the GlassFish Update Center. A rapid deployment technology for Web developers is featured in v3 Prelude as well.

The v3 Prelude application server features a subset of the full v3 application server, which can be used mission-critical applications.

Support for v3 Prelude costs US$4,500 for a four-socket subscription.