public final static BrokerPool getInstance() throws EXistException { return getInstance(DEFAULT_INSTANCE);
public final static BrokerPool getInstance(String id) throws EXistException { BrokerPool instance = (BrokerPool) instances.get(id); if (instance != null) return instance; else throw new EXistException("instance with id " + id + " has not been configured yet");
	public final static BrokerPool getInstance() throws EXistException {		return getInstance(DEFAULT_INSTANCE);	}