@Override
 protected String toStringPollSource() {
   if (callable == null) return null;
   String cs = callable.toString();
   if (!cs.contains("" + Integer.toHexString(callable.hashCode()))) {
     return cs;
   }
   // if hashcode is in callable it's probably a custom internal; return class name
   return JavaClassNames.simpleClassName(callable);
 }