IF condition on empty Collection has different behavior than null Collection

@CompileStatic
class NotWorkingExample {
  static void main(String[] args) {
    Collection<String> values = null
    for (i in 0..<200_000) {
      printSomethingIfNotEmpty(values)
    }

    //never printed but it should
    values = ['A']
    printSomethingIfNotEmpty(values)
  }

  static printSomethingIfNotEmpty(Collection<String> values) {
    if(values) {
      println 'something'
    }
  }
}

@CompileStatic
class ItWorks {
  static void main(String[] args) {
      Collection<String> values = []
      for (i in 0..<200_000) {
        printSomethingIfNotEmpty(values)
      }

    //it works because [] was passed in the previous 200k calls
    values = ['A']
    printSomethingIfNotEmpty(values)
  }

  static printSomethingIfNotEmpty(Collection<String> values) {
    if(values) {
      println 'something'
    }
  }
}