Groovy Goodness: Sorting a List of Map by specific Key

Sorting a Map by value with Groovy is very simple, due to the added ‘sort’ method on the Map interface.
def hashMap = "fields": {
      "field_3": {
        "order": 4
      },
      "field_2": {
        "order": 3
      },
      "field_1": {
        "order": 2     
    },
      "field_0": {
        "order": 6   
      }
    }

hashMap.sort { a , b -> a.value.order <=> b.value.order }