question: public Artifact ( final String group , final String artifact , final String version ) { if ( group == null || group . isEmpty ( ) ) throw new IllegalArgumentException ( "group cannot be null or empty" ) ; if ( artifact == null || artifact . isEmpty ( ) ) throw new IllegalArgumentException ( "artifact cannot be null or empty" ) ; if ( version == null || version . isEmpty ( ) ) throw new IllegalArgumentException ( "version cannot be null or empty" ) ; this . group = group ; this . artifact = artifact ; this . version = version ; }
target:  Create a new instance.