public static Collection<String> logFiles(){
  Collection<String> res=new ArrayList<>(fileAppenders.size());
  for (  FileAppender a : fileAppenders)   res.add(a.getFile());
  return res;
}

public static Collection < String > logFiles ( ) { Collection < String > res = new ArrayList < > ( fileAppenders . size ( ) ) ; for ( FileAppender a : fileAppenders ) res . add ( a . getFile ( ) ) ; return res ; }
gets files for all registered file appenders .
