code: public ZooJdoProperties setOptimistic(boolean flag) {
      	DBTracer.logCall(this, flag); 
  		put(Constants.PROPERTY_OPTIMISTIC, Boolean.toString(flag));
  		if (flag) {
  			throw new UnsupportedOperationException();
  		}
  		return this;
  	}
docs: Whether the transactions should be optimistic, that means whether objects should become
  non-transactional during commit. This is for example useful when objects should be
  accessible outside transactions. This is optimistic, because less consistency guarantees
  are given.
  @param flag The flag
  @return this
  @see Constants#PROPERTY_OPTIMISTIC