Sending email in grails from a java class

I have a grails app with MailService plugin. I need to send an email from a java class using sendMail(Closure callable) method.

From a groovy class I do it the next way:

mailService.sendMail
{
   to ["test@gmail.com"]
   subject "Mail Subject"
   body "this is a message body")
}

How can I do the same from a java class?