Since Groovy 1.7.2 we can use the leftShift() method (<< operator) to add a map to another map.
def m = [name: 'Java', max: 10, sort: 'name'] def other = [name: 'Groovy', direction: 'asc'] m << other assert [name: 'Groovy', max: 10, sort: 'name', direction: 'asc'] == m
