code: public static FieldExtension getField(DelegateExecution execution,
                                            String fieldName) {
          if (isExecutingExecutionListener(execution)) {
              return getListenerField(execution,
                                      fieldName);
          } else {
              return getFlowElementField(execution,
                                         fieldName);
          }
      }
docs: Returns the {@link FieldExtension} matching the provided 'fieldName' which
  is defined for the current activity of the provided
  {@link DelegateExecution}.
  <p>
  Returns null if no such {@link FieldExtension} can be found.
  <p>
  If the execution is currently being used for executing an
  {@link ExecutionListener}, the field of the listener will be returned. Use
  {@link #getFlowElementField(DelegateExecution, String)} or
  {@link #getListenerField(DelegateExecution, String)} for specifically
  getting the field from either the flow element or the listener.