JSONBuilder in Grails console

I'm t开发者_Go百科rying to use the Groovy JSONBuilder in the Grails (2.0.0.M2) console. When I execute the following

import grails.web.JSONBuilder                

def builder = new JSONBuilder()

def result = builder.build {
    foo = 'bar'    
}

result.toString()

I get the error:

org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'bar' with class 'java.lang.String' to class 'grails.converters.JSON'

at grails.web.JSONBuilder.build(JSONBuilder.groovy:39)

The builder seems to work fine in the app itself. Is there a reason why it doesn't work in the console?

While i was working with JSONBuilder, i faced similar problems, then i decide to not use JSONBuilder. If it is not necessary for you, you can change your builder.

import org.codehaus.groovy.grails.web.json.*; 
import grails.converters.JSON;             

def result =[:]
result.foo='bar'

println result as JSON

it's result will be same.