Code improvement: Consider using method reference instead of a lambda, for example:

Change this
AccessibleRole role =
  InvocationUtils.invokeAndWait(() -> { return ac.getAccessibleRole(); }, ac);

to this
AccessibleRole role =
  InvocationUtils.invokeAndWait(ac::getAccessibleRole, ac);

And also change all places where "InvokeAndWait(new Callable ..." is used.