def person1 = [firstName:"RJ", lastName:"Salicco", toString:{ return "$firstName $lastName" }] as Expando
def person2 = [firstName:"Mike", lastName:"Test", toString:{ return "$firstName $lastName" }] as Expando
def person3 = [firstName:"Test", lastName:"Value", toString:{ return "$firstName $lastName" }] as Expando

interface Service {
    void doWork(Object... o)
}

impl = { args -> 
    c = args[-1]
    if(c instanceof Closure)
        c.call(args-c)
    else 
        args.each { println "$it " }
} as Service

impl.doWork(person1, person2, person3)
impl.doWork(person1, person2, person3) { a, b, c ->
    println "$a, $b, $c [I wanted something different!]"
}