Support for JSON in Oracle 11g
No, JSON support was introduced in Oracle database 12c release 2 (12.1.0.2)
Regards
If you install the latest APEX 5.0 which was released on April 15. You get access to a great API to work with JSON
I'm using it on 11.2 and have been able to crunch every single json, from simple to very complex objects with multiple arrays and 4/5 levels. APEX_JSON
If you do not want to use APEX. Simply install the runtime environment to get access to the API.