Camunda - Dynamically created model causes "java.lang.ClassNotFoundException" when calling TaskListener class

I have a series of models defined in XML. We now have a required to create models dynamically without the need for XML files and any restart of the Camunda web app.

I have implemented the dynamic model and deploy as such (modelInstance is a BpmnModelInstance object):

BpmPlatform.getProcessEngineService()
                    .getProcessEngine("default")
                    .getRepositoryService()
                    .createDeployment().addModelInstance("bpmn", modelInstance)
                    .deploy();

but when the model is deployed and instantiated the following error is thrown:

Caused by: org.camunda.bpm.engine.ProcessEngineException: ENGINE-09008 Exception while instantiating class 'org.camunda.bpm.utility.AssignmentAPINotify': ENGINE-09017 Cannot load class 'org.camunda.bpm.utility.AssignmentAPINotify': org.camunda.bpm.utility.AssignmentAPINotify
    at org.camunda.bpm.engine.impl.util.EngineUtilLogger.exceptionWhileInstantiatingClass(EngineUtilLogger.java:78)
    at org.camunda.bpm.engine.impl.util.ClassDelegateUtil.instantiateDelegate(ClassDelegateUtil.java:50)
    at org.camunda.bpm.engine.impl.task.listener.ClassDelegateTaskListener.getTaskListenerInstance(ClassDelegateTaskListener.java:54)
    at org.camunda.bpm.engine.impl.task.listener.ClassDelegateTaskListener.notify(ClassDelegateTaskListener.java:42)
    at org.camunda.bpm.engine.impl.task.delegate.TaskListenerInvocation.invoke(TaskListenerInvocation.java:41)
    at org.camunda.bpm.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:54)
    at org.camunda.bpm.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocationInContext(DefaultDelegateInterceptor.java:87)
    at org.camunda.bpm.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:59)
    at org.camunda.bpm.engine.impl.persistence.entity.TaskEntity.fireEvent(TaskEntity.java:956)
    ... 119 more
Caused by: org.camunda.bpm.engine.ClassLoadingException: ENGINE-09017 Cannot load class 'org.camunda.bpm.utility.AssignmentAPINotify': org.camunda.bpm.utility.AssignmentAPINotify
    at org.camunda.bpm.engine.impl.util.EngineUtilLogger.classLoadingException(EngineUtilLogger.java:135)
    at org.camunda.bpm.engine.impl.util.ReflectUtil.loadClass(ReflectUtil.java:107)
    at org.camunda.bpm.engine.impl.util.ClassDelegateUtil.instantiateDelegate(ClassDelegateUtil.java:42)
    ... 126 more
Caused by: java.lang.ClassNotFoundException: org.camunda.bpm.utility.AssignmentAPINotify
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1275)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1104)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.camunda.bpm.engine.impl.util.ReflectUtil.loadClass(ReflectUtil.java:84)
    ... 127 more

If I save the model as XML and restart there isn't any issue.

I have been seeing if deploymentBuilder.addClasspathResource(""); is the solution but nothing seems to work!

I resolved this by registering the deployment to the process application using the management service

            ProcessEngine processEngine = BpmPlatform.getProcessEngineService().getDefaultProcessEngine();
            DeploymentBuilder deploymentBuilder = processEngine.getRepositoryService().createDeployment();
            deploymentBuilder = deploymentBuilder.addModelInstance(name, modelInstance);
            Deployment deployment = deploymentBuilder.deploy();
                        
            ManagementService managementService = processEngine.getManagementService();
            managementService.registerProcessApplication(deployment.getId(), PROCESS_APPLICATION_REFERENCE);

This was solved with the help of the Camunda forum.