[JENKINS-28510] DescribableHelper error with @DataBoundSetter on Map<String,String>

I'm working on implementing a new step in a plugin, and came across the following error:

If one argument step is a Map, and it is a field annotated with @​DataBoundSetter, Ok, no problems. But if it is a Setter annotated with @​DataBoundSetter the following error occurs during instantiation:

java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.ParameterizedTypeImpl cannot be cast to java.lang.Class

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.coerce(DescribableHelper.java:214)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.buildArguments(DescribableHelper.java:186)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.injectSetters(DescribableHelper.java:308)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.instantiate(DescribableHelper.java:93)

	at org.jenkinsci.plugins.workflow.steps.StepDescriptor.newInstance(StepDescriptor.java:95)

	at org.jenkinsci.plugins.workflow.cps.DSL.invokeMethod(DSL.java:133)

	at org.jenkinsci.plugins.workflow.cps.CpsScript.invokeMethod(CpsScript.java:100)

	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:45)

	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)

	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)

	at com.cloudbees.groovy.cps.sandbox.DefaultInvoker.methodCall(DefaultInvoker.java:15)

	at WorkflowScript.run(WorkflowScript:5)

...

Apparently the error is in injectSetters() method of the class DescribableHelper

---
Originally reported by valones, imported from: DescribableHelper error with @DataBoundSetter on Map

• assignee: jglick
  
• status: Reopened
  
• priority: Minor
  
• component(s): structs-plugin
  
• label(s): pipeline
  
• resolution: Unresolved
  
• votes: 1
  
• watchers: 3
  
• imported: 20260604-211335
  

I'm working on implementing a new step in a plugin, and came across the following error:

 If one argument step is a Map, and it is a field annotated with @DataBoundSetter, Ok, no problems. But if it is a Setter annotated with @DataBoundSetter the following error occurs during instantiation:




java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.ParameterizedTypeImpl cannot be cast to java.lang.Class

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.coerce(DescribableHelper.java:214)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.buildArguments(DescribableHelper.java:186)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.injectSetters(DescribableHelper.java:308)

	at org.jenkinsci.plugins.workflow.structs.DescribableHelper.instantiate(DescribableHelper.java:93)

	at org.jenkinsci.plugins.workflow.steps.StepDescriptor.newInstance(StepDescriptor.java:95)

	at org.jenkinsci.plugins.workflow.cps.DSL.invokeMethod(DSL.java:133)

	at org.jenkinsci.plugins.workflow.cps.CpsScript.invokeMethod(CpsScript.java:100)

	at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.call(PogoMetaClassSite.java:45)

	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)

	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)

	at com.cloudbees.groovy.cps.sandbox.DefaultInvoker.methodCall(DefaultInvoker.java:15)

	at WorkflowScript.run(WorkflowScript:5)

...





Apparently the error is in injectSetters() method of the class DescribableHelper

environment

```
Jenkins 1.609

workflow-plugin 1.6
```