GlassFish 3.1 brings together the benefits of GlassFish v3 and GlassFish
v2.x with lots of net new features (see blog
<http://blogs.sun.com/arungupta/entry/glassfish_3_1_glassfish_2>). It is
based on world’s first implementation of Java EE 6 with an OSGi based
flexible, lightweight, extensible platform. It requires a small memory
footprint. It is fully featured with production-ready features such as
clustering and high availability, provides optimized runtime performance
and ready for enterprise deployments.