As described in GRECLIPSE-871, the code assist templates in the Groovy editor are Java templates. We should remove all of them and replace them with Groovy variants.
main() method added by New Wizard vs added by content assist
Expected a patch for this, but it never came. Won't fix for 2.6.0.
Now available in 2.8.0 build snapshots. Preferences -> Groovy -> Editor -> Templates now allows you to tweak groovy editor templates. Java templates have been removed.