# Flowable Custom Function Delegate error

**URL:** <https://forum.flowable.org/t/flowable-custom-function-delegate-error/7100>\
**Category:** Flowable Engine\
**Created:** [November 19, 2020, 1:28pm UTC](https://forum.flowable.org/t/flowable-custom-function-delegate-error/7100 "2020-11-19T13:28:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Poojitha](https://avatars.discourse-cdn.com/v4/letter/p/779978/32.png) [@Poojitha](https://forum.flowable.org/u/Poojitha)\
**Post date:** [November 19, 2020, 1:28pm UTC](https://forum.flowable.org/t/flowable-custom-function-delegate-error/7100/1 "2020-11-19T13:28:54Z")

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Hi Team,  
Iam getting error -_ **"org.flowable.common.engine.api.FlowableException: Could not resolve function 'custom:testFunctionName’**._ while executing rules through JULE expressions.  
i have created class-  
@Component  
public class CustomFlowableFunctionDelegate extends AbstractFlowableFunctionDelegate {

@Override  
public String prefix() {  
return “custom”;  
}

@Override  
public String localName() {  
return “testFunctionName”;  
}

@Override  
public Class\<?\> functionClass() {  
return CollectionUtil.class;  
}

@Override  
public Method functionMethod() {  
return getTwoObjectParameterMethod();  
}  
}  
and implemented testFunctionName method which returns true always in package - package org.flowable.dmn.engine.impl.el.util;

package org.flowable.dmn.engine.impl.el.util;  
@Component  
public class CollectionUtil {

public static boolean testFunctionName(Object collection, Object value) {  
return true;  
}  
}

and my expression is : ${“custom:testFunctionName(’’,’’)”}

could you guys please help to me solve this out.

Thankyou  
Poojitha.

---

<div class="post-metadata">

**Author:** ![amporsim](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@amporsim](https://forum.flowable.org/u/amporsim)\
**Post date:** [November 20, 2020, 7:22am UTC](https://forum.flowable.org/t/flowable-custom-function-delegate-error/7100/2 "2020-11-20T07:22:38Z")

</div>

Hi @Poojitha

Have you also registered your `CustomFlowableFunctionDelegate` as a `customFlowableFunctionDelegates` in the appropriate engine?

Example for the DMN engine: [https://flowable.com/open-source/docs/dmn/ch02-Configuration/#custom-flowable-function-delegates](https://flowable.com/open-source/docs/dmn/ch02-Configuration/#custom-flowable-function-delegates)

Regards,  
Simon