Oracle JSON related PL/SQL types: Reference semantics

declare
   jsn json_object_t;
  
   ary json_array_t;
   obj json_object_t;
begin
 
   jsn := json_object_t.parse('{
      "scl":  17,
      "ary": [1,2,3],
      "obj": {"num": 42}
   }');
  
   ary := jsn.get_array('ary');
   ary.append(4);
  
   obj := jsn.get_object('obj');
   obj.put('txt','Hello world');
  
   dbms_output.put_line(jsn.to_string(pretty=>true));
  
end;
/
--
-- {
--   "scl" : 17,
--   "ary" :
--   [
--     1,
--     2,
--     3,
--     4
--   ],
--   "obj" :
--   {
--     "num" : 42,
--     "txt" : "Hello world"
--   }
-- }