# Error serializing class instance into json in 8.0.14 **URL:** \ **Category:** Ignition\ **Created:** [July 15, 2020, 2:09am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708 "2020-07-15T02:09:22Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![kgamble](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kgamble/32/8019_2.png) [@kgamble](https://forum.inductiveautomation.com/u/kgamble)\ **Post date:** [July 15, 2020, 2:09am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/1 "2020-07-15T02:09:22Z")
I am trying to serialize a python class into json, and it works fine and great in python 2.7 and 3.8 But when I try to test it out in the script console it shows an issue with the `stringmap` type containing the ` __dict__ ` method. I dont see the same issue in any regular python interpreter, so I am curious if this is a Jython issue and something I am potentially missing. ```auto import json class Operation(): def __init__ (self, name): self.name = name def __repr__ (self): return json.dumps(operation, default=ComplexEncoder) def ComplexEncoder(obj): print('Encoding the json...') return obj. __dict__ operation = Operation("Part 1: Base") #Encode the operation object into a json jsonStr = json.dumps(operation, default=ComplexEncoder) print("Encoded JSON:",jsonStr) ``` What else is interesting, is in Jython it actually runs the encoder function twice for some reason, printing “Encoding the json…” twice? Whereas in regular python it only runs the function once. Any ideas would be greatly appreciated! EDIT: To clarify, it runs the `ComplexEncoder` method twice even when I comment out the ` __repr__ ` method and the line printing at the end like so: ```auto import json class Operation(): def __init__ (self, name): self.name = name # def __repr__ (self): # return json.dumps(operation, default=ComplexEncoder) def ComplexEncoder(obj): print('Encoding the json...') return obj. __dict__ operation = Operation("Part 1: Base") #Encode the operation object into a json jsonStr = json.dumps(operation, default=ComplexEncoder) #print("Encoded JSON:",jsonStr) ``` ---
**Author:** ![Sanderd17](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sanderd17/32/8735_2.png) [@Sanderd17](https://forum.inductiveautomation.com/u/Sanderd17)\ **Post date:** [July 15, 2020, 6:34am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/2 "2020-07-15T06:34:44Z")
[https://docs.python.org/2/library/json.html](https://docs.python.org/2/library/json.html) > New in version 2.6. The json module doesn't exist in version 2.5. Not sure where you got your json import from. ---
**Author:** ![kgamble](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kgamble/32/8019_2.png) [@kgamble](https://forum.inductiveautomation.com/u/kgamble)\ **Post date:** [July 15, 2020, 10:31am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/3 "2020-07-15T10:31:53Z")
Weird I didn’t add it or anything? Any chance ignition is pre-packaging it to help with some things like system.util.jsonEncode or jsonDecode? ---
**Author:** ![Sanderd17](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sanderd17/32/8735_2.png) [@Sanderd17](https://forum.inductiveautomation.com/u/Sanderd17)\ **Post date:** [July 15, 2020, 10:34am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/4 "2020-07-15T10:34:14Z")
Which version are you using? On a 7.9.4 I was using, it gave an error. While that version does already have `jsonEncode` and `jsonDecode` system functions. ---
**Author:** ![kgamble](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kgamble/32/8019_2.png) [@kgamble](https://forum.inductiveautomation.com/u/kgamble)\ **Post date:** [July 15, 2020, 10:53am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/5 "2020-07-15T10:53:06Z")
I was using 8.0.14, good call normal i put that in my intro and forgot. ---
**Author:** ![Sanderd17](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sanderd17/32/8735_2.png) [@Sanderd17](https://forum.inductiveautomation.com/u/Sanderd17)\ **Post date:** [July 15, 2020, 10:54am UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/6 "2020-07-15T10:54:13Z")
Ah, in that case, you’re even running Jython 2.7. And my remarks don’t count. ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [July 15, 2020, 2:52pm UTC](https://forum.inductiveautomation.com/t/error-serializing-class-instance-into-json-in-8-0-14/36708/7 "2020-07-15T14:52:08Z")
It’s running twice because your encoder is being called to serialize the `dict` returned by `obj. __dict__ ` after the first call. I’ll have to chalk that up to a problem with Jython - while Python’s `json.dumps` is a pretty awful API for writing a serialization mechanism (in my ~~humble~~ opinion), it’s certainly able to handle this simple case. _If_ you only need to serialize domain-specific objects, it should be too bad to essentially write your own traversal scheme that takes an input object, walks down its members, and returns a plain Python structure that can be passed to system.util.jsonEncode as @Sanderd17 suggested.