@Override
        public void initialize(TaskReferenceNameUniqueConstraint constraintAnnotation) {}
This constraint class validates following things.

<ul>
  <li>1. WorkflowDef is valid or not
  <li>2. Make sure taskReferenceName used across different tasks are unique
  <li>3. Verify inputParameters points to correct tasks or not
</ul>
common/src/main/java/com/netflix/conductor/common/constraints/TaskReferenceNameUniqueConstraint.java