code: public static String getJSON(Object obj, ObjectInspector objIns) {
          StringBuilder sb = new StringBuilder();
          buildJSONString(sb, obj, objIns);
          return sb.toString();
      }
docs: Get serialized json using an orc object and corresponding object
  inspector Adapted from
  {@link org.apache.hadoop.hive.serde2.SerDeUtils#getJSONString(Object, ObjectInspector)}
  
  @param obj
  @param objIns
  @return