gistfile1.txt

JS:
function makeDoubler() {
  var a = 1
  return function() {
    a = a * 2;
    return a;
  }
}

Java:
Function makeDoubler() {
  final Array<int> a = new Array<int>[1];
  a[0] = 1;
  return new Function<int>() {
    @Override
    int apply() {
      a[0] = a[0] * 2;
      return a[0];
    }
  }
}