def words = ['Groovy', 'Rocks', 'Big', 'Time']

def result = words.collectEntries {
    [(it): it.contains('o')]
}

assert result.Groovy && result.Rocks
assert !result.Big && !result.Time

//invert map
inverted_map = map.collectEntries { k,v -> [(v):k] }

// another weird semi-related datastructure manipulation
import groovy.json.*

def map = ["Server":"ABC", "Database":"sa"]

def list = map.inject([]) { result, k, v ->
    result << ['key': k, 'value': v]
    result
}

println new JsonBuilder(list).toString()