JLine minimum sample in Groovy.

helloJLine.groovy

@GrabResolver(name='jline', root='http://jline.sourceforge.net/m2repo')
@Grab(group='jline', module='jline', version='0.9.9')
import jline.*

def prompt(ConsoleReader reader, String msg, Closure clos) {
  while (true) {
    def line = reader.readLine(msg)
    if (line in [null, 'exit']) break
    clos(line)
  }
}

def reader = new ConsoleReader()
reader.bellEnabled = false

prompt(reader, '> ') { line -> 
  println "--> [${line}]"
}