question: public Name add ( int posn , Rdn comp ) { if ( comp == null ) { throw new NullPointerException ( "Cannot set comp to null" ) ; } rdns . add ( posn , comp ) ; unparsed = null ; return this ; }
target:  Adds a single RDN at a specified position within this LDAP name. RDNs of this LDAP name at or after the index (if any) of the new RDN are shifted up by one (away from index 0) to accommodate the new RDN.