Recently Guillaume Laforge, the Groovy Project Manager, posted about the release of both Groovy 1.5.7 and Groovy 1.6-beta-2 on his blog. The 1.5.x branch is the current stable release of Groovy that is being maintained while the steady development of 1.6 continues.
The primary focus for 1.6 is improving performance during compile-time and runtime. Back on May 2, 2008 the first beta for the 1.6 branch was released which announced significant performance improvements,
...the compiler is 3 to 5 times faster than in previous releases. This improvement is available both in this development version and in the 1.5.x stable branch. Thanks to class lookup caches, the bigger the project, the faster the compilation will be.
However, the most noticeable changes will be in the general runtime performance improvements of Groovy. We used several benchmarks from the Great Language Shootout to measure our progress. On those we selected, compared to the current Groovy 1.5.6 stable release, the performance improvements range from 150% to 460%. Micro-benchmarks obviously don't reflect the kind of code you have in your own projects, but the overal performance of your projects should improve significantly.
Andrew Glover interviewed Guillaume Laforge in a podcast in which he asked why the central theme for Groovy 1.6 was focused on improving performance. Guillaume explains that performance related complaints are typically being found in the blogosphere amongst developers performing their own benchmarks as opposed to coming directly from customers. Guillaume did go on to say that the focus on improving performance was to help all Groovy users, but was also so that Groovy could "play better to the others", as in programming languages.
Amidst the activity surrounding Groovy 1.6, the Groovy Roadmap has plans outlined for versions 1.7 and 2.0. Looking at the history of that wiki page you can see that plans for Groovy 1.8 were erased and subsequently moved into 1.7, as features planned for 1.7 have been implemented in 1.6 such as AST Transformations.
In Andrew Glover's podcast with Guillaume Laforge, it was mentioned that a final release of Groovy 1.6 could possibly be expected in September 2008. Instead 1.6-beta-2 was released. More details can be found on the Groovy mailing list, however, Guillaume made it clear that as long as the integration of Groovy 1.6 and Grails is failing it will not be released.
For more information try following these links: