I use file .ftl (freemarker template)
and need syntax color.
I like to use vim syntax system unless netbeans for some file like .ftl
In NetBeans syntax highlighting is done by the editor infrastructure. jVi has nothing to do with it.
You might try asking in some of NetBeans' forums about syntax highlighing for .ftl files. Perhaps there is something in progress. Designing a language syntax/highlighting is documented if you are interested in doing that.
It might be possible to design a syntax highlighter that plugs in to NetBeans and which translates and/or interprets vim syntax files. I encourage you to check out the syntax highlighting SPI in NetBeans; perhaps this would be a project you'd like to undertake. It seems like it could be done without any changes to jVi.