I have Java backend project with REST implementation which is a warfile, 
 I also have Grails as frontend, i can run theese two separeted projects on their own using tomcat, 

but how do i configure the grails part so that i can use the java backend RESTfull webbservice within it, 

do i have to make a war file from the java backend and import it to the grails frontend ? make a jarfile ? 

if so, how do i do that ? or are there any other way to to this to make it work.