Hidden features of Groovy?

Answer 1

How to build a JSON tree in a couple of lines in groovy ?

1) define your tree with self-referential withDefault closure

def tree // declare  first before using a self reference
tree = { ->  [:].withDefault{ tree() } }

2) Create your own JSON tree

frameworks = tree()
frameworks.grails.language.name = 'groovy'
frameworks.node.language.name = 'js'

def result =  new groovy.json.JsonBuilder(frameworks)

Which gives: {"grails":{"language":{"name":"groovy"}},"node":{"language":{"name":"js"}}}