In the apache netbeans blog there is a post about plugins for netbeans 9.
In brief, you need to use the nb 8.2 update center.
On Sat, 11 Aug 2018, 07:49 Peter Steele, <steeleh...@gmail.com> wrote:
> I recently tried to upgrade from a pre 9.0 release in April to the 9.0
> release not that is has been released. I have found an issue on the
> migration though.
> The update center has changed now and I can no longer install Groovy and
> Grails plugin and because of this the Gradle plugin doesn't work anymore
> (and all my projects use gradle)
> Is there a way to get around this?