Building json using JsonOutput

Here one way of doing using jackson libraries:

import com.fasterxml.jackson.annotation.JsonProperty
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.SerializationFeature

class Synchronize {
    String method
    String path
    @JsonProperty("synchronization-type")
    int synchronizationType
}

def synch = new Synchronize(method:'GET', path:'news', synchronizationType:2)
ObjectMapper mapper = new ObjectMapper()
mapper.configure(SerializationFeature.INDENT_OUTPUT,true)
println(mapper.writeValueAsString(synch))

Get the depenency libraries from here

OUTPUT

{
  "method" : "GET",
  "path" : "news",
  "synchronization-type" : 2
}

Another simplest way to produce the same output(without having to use java object ) and without additional third party libraries

import groovy.json.JsonBuilder
def json = new JsonBuilder()
json {
    method 'GET'
    path 'news'
    "synchronization-type" 2
}
println json.toPrettyString()

You may also look at the link for array example