Type 1120 Access of undefined property JSON
If you were working with Flex 4/3 or any lesser versions of Flex, you would be using corelib.swc or as3corelib.swc to access JSON property.
You also would have imported something like import com.adobe.serialization.json.JSON;
Well with Flex 4.6 it is not necessary either the swc or import any package is not necessary.
if you are getting this error Type 1120 Access of undefined property JSON
You just need to remove the above mentioned import and
and then you’ll need to modify the code,
JSON.decode(myString); to JSON.parse(myString);
JSON.encode(myObject); to JSON.stringify(myObject);