question: public final Set < String > aliases ( ) { if ( aliasSet != null ) return aliasSet ; int n = aliases . length ; HashSet < String > hs = new HashSet < String > ( n ) ; for ( int i = 0 ; i < n ; i ++ ) hs . add ( aliases [ i ] ) ; aliasSet = Collections . unmodifiableSet ( hs ) ; return aliasSet ; }
target:  Returns a set containing this charset's aliases.