public static Set<String> putSetIntoMap(String key,Map<String,Set<String>> map,String value){
  Set<String> set=new HashSet<String>();
  set.add(value);
  map.put(key,set);
  return set;
}

public static Set < String > putSetIntoMap ( String key , Map < String , Set < String > > map , String value ) { Set < String > set = new HashSet < String > ( ) ; set . add ( value ) ; map . put ( key , set ) ; return set ; }
returns set of string . this is a convenient method for adding a set of string into a map . in this project , we usually have the < code > map & lt ; string , set & lt ; string & gt ; & gt ; and many times , we just want to add a string to the map .
