Golo supports null-safe methods invocations using the "Elvis" symbol: ?:.

Suppose that we invoke the method bar() on some reference foo: foo: bar(). If foo is null, then invoking bar() throws a java.lang.NullPointerException, just like you would expect in Java.

By contrast:

This is quite useful when querying data models where null values could be returned. This can be elegantly combined with the orIfNull operator to return a default value, as illustrated by the following example:

let person = dao: findByName("Mr Bean")
let city = person?: address()?: city() orIfNull "n/a"

This is more elegant than, say:

let person = dao: findByName("Mr Bean")
var city = "n/a"
if person isnt null {
  let address = person: address()
  if address isnt null {
    city = address: city() ofIfNull "n/a"
  }
}