private static void cleanDirectory(File path){
  if (path == null)   return;
  if (path.exists()) {
    for (    File f : path.listFiles()) {
      if (f.isDirectory())       cleanDirectory(f);
      f.delete();
    }
  }
}

private static void cleanDirectory ( File path ) { if ( path == null ) return ; if ( path . exists ( ) ) { for ( File f : path . listFiles ( ) ) { if ( f . isDirectory ( ) ) cleanDirectory ( f ) ; f . delete ( ) ; } } }
recursive remove all from directory
