code: public void setAddress(final String address) {
  		// Do we have a subaddressing account?
  		Preconditions.checkArgument(StringUtils.startsWith(this.address, accountId + "+"),
  				"Mail address can only be changed when subaddressing is active");
  		Preconditions.checkArgument(StringUtils.startsWith(address, accountId), "New mail address %s does not start with accountId=%s", address,
  				accountId);
  		log.info("Changing mail address from {} to {}", this.address, address);
  		this.address = address;
  	}
docs: Allows to set a new mail address. This is only possible when mail subaddressing is active and
  the new mail address belongs to the defined mail accountId.
  
  @param address
  the new mail address