cd.clear();
clearEventContext();
	private Principal clearAndCheckPrincipal() {		// clear even if this fails. (make SecuritySystem unusable)		cd.clear();				final Principal p = principalHolder.get();				if (p == null)			throw new SecurityViolation(					"Principal is null. Not logged in to SecuritySystem.");		if (p.getName() == null)			throw new InternalException(					"Principal.name is null. Security system failure.");		if (p.getGroup() == null)			throw new InternalException(					"Principal.group is null in EventContext. Security system failure.");				if (p.getEventType() == null)			throw new InternalException(					"Principal.eventType is null in EventContext. Security system failure.");		return p;	}