# Setting my deserializer causes ui-app docker not to start

**URL:** <https://forum.flowable.org/t/setting-my-deserializer-causes-ui-app-docker-not-to-start/7055>\
**Category:** Flowable Engine\
**Created:** [November 10, 2020, 10:18am UTC](https://forum.flowable.org/t/setting-my-deserializer-causes-ui-app-docker-not-to-start/7055 "2020-11-10T10:18:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![iadded](https://avatars.discourse-cdn.com/v4/letter/i/9dc877/32.png) [@iadded](https://forum.flowable.org/u/iadded)\
**Post date:** [November 10, 2020, 10:18am UTC](https://forum.flowable.org/t/setting-my-deserializer-causes-ui-app-docker-not-to-start/7055/1 "2020-11-10T10:18:24Z")

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Hi

I’m using the Flowable-ui docker to run my apps (configured it to work against my mysqldb).  
I’m running a springboot application with the flowable engine - and all is working fine.

But now - i had to override the json deserializer in order to perform json-schema validation for my incoming events.

In my inbound channel config file i added the following:  
“deserializerDelegateExpression”: “{flowerJsonWithValidatorDeserializer}", "payloadExtractorDelegateExpression":"{flowerJsonFieldToMapPayloadExtractor}”,

And everything works fine - my deserializer is working as expected - and flow run correctly.

But - when i stop my app docker - and try to restart it - it fails to restart with following error:  
org.flowable.common.engine.api.FlowableException: Unknown property used in expression: ${flowerJsonWithValidatorDeserializer}

Any advice will be appreciated  
Thanks  
Inbal

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<div class="post-metadata">

**Author:** ![joram](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.flowable.org/joram/32/26_2.png) [@joram](https://forum.flowable.org/u/joram)\
**Post date:** [November 16, 2020, 8:17pm UTC](https://forum.flowable.org/t/setting-my-deserializer-causes-ui-app-docker-not-to-start/7055/2 "2020-11-16T20:17:41Z")

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How are you adding your bean ‘flowerJsonWithValidatorDeserializer’ to the docker container in the first place? How are you configuring the engine configuration?

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<div class="post-metadata">

**Author:** ![iadded](https://avatars.discourse-cdn.com/v4/letter/i/9dc877/32.png) [@iadded](https://forum.flowable.org/u/iadded)\
**Post date:** [November 17, 2020, 6:07am UTC](https://forum.flowable.org/t/setting-my-deserializer-causes-ui-app-docker-not-to-start/7055/3 "2020-11-17T06:07:46Z")

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Thanks for replying  
I have the UI Apps running on a docker against my mysqldb - using the rest api that runs as part of the flowable-ui docker. (i’m thinking maybe this is the problem - maybe i should make the UI work against the rest api exposed by my springboot app instead ?)

My springboot app runs against the same db.  
In my springboot app i created the flowerJsonWithValidatorDeserializer & flowerJsonFieldToMapPayloadExtractor both are spring components.

In my inbound channel file i configured the channel to use those:  
{  
“key”: “flowerInboundChannel”,  
“name”: “Flower Inbound Channel”,  
“description”: “Flower Inbound Channel”,  
“channelType”: “inbound”,  
“type”: “rabbit”,  
“deserializerType”: “expression”,  
“deserializerDelegateExpression”: “{flowerJsonWithValidatorDeserializer}", "payloadExtractorDelegateExpression":"{flowerJsonFieldToMapPayloadExtractor}”,  
“channelEventKeyDetection”: {  
“jsonField”: “msgKey”  
},  
“queues”: [“flowerEventsQueue”]  
}

And indeed they are called when events arrive on the channel.

Problem is that if i stop the UI app docker and try to start it again - i get the following error:  
org.flowable.common.engine.api.FlowableException: Unknown property used in expression: ${flowerJsonWithValidatorDeserializer}

Will appreciate any advice on this one  
Thanks  
Inbal