# Rhino Usage Warning message for Query Builder

**URL:** <https://forum.servoy.com/t/rhino-usage-warning-message-for-query-builder/20071>\
**Category:** Classic Servoy\
**Created:** [August 23, 2019, 1:42pm UTC](https://forum.servoy.com/t/rhino-usage-warning-message-for-query-builder/20071 "2019-08-23T13:42:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![joe26](https://avatars.discourse-cdn.com/v4/letter/j/ce7236/32.png) [@joe26](https://forum.servoy.com/u/joe26)\
**Post date:** [August 23, 2019, 1:42pm UTC](https://forum.servoy.com/t/rhino-usage-warning-message-for-query-builder/20071/1 "2019-08-23T13:42:14Z")

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Good Day!

What is the meaning / severity of this error?

> RHINO USAGE WARNING: Missed Context.javaToJS() conversion:
> 
> Rhino runtime detected object com.servoy.j2db.querybuilder.impl.QBJoin@adfd76 of class com.servoy.j2db.querybuilder.impl.QBJoin where it expected String, Number, Boolean or Scriptable instance. Please check your code for missing Context.javaToJS() call.

What causes this warning? Is an empty join being made on a table?

Thanks!  
–Joe.

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**Author:** ![joe26](https://avatars.discourse-cdn.com/v4/letter/j/ce7236/32.png) [@joe26](https://forum.servoy.com/u/joe26)\
**Post date:** [September 20, 2019, 1:38pm UTC](https://forum.servoy.com/t/rhino-usage-warning-message-for-query-builder/20071/2 "2019-09-20T13:38:58Z")

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Anyone have info on this warning and its impact?

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**Author:** ![Andrei\_Costescu](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Andrei\_Costescu](https://forum.servoy.com/u/Andrei_Costescu)\
**Post date:** [September 24, 2019, 10:20am UTC](https://forum.servoy.com/t/rhino-usage-warning-message-for-query-builder/20071/3 "2019-09-24T10:20:42Z")

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Do you have a sample that shows this?