public File tmpDir(){
  String random=String.valueOf(RANDOM.nextLong());
  File dir=tmpFile("dir" + random);
  assureDirExists(dir);
  return dir;
}

public File tmpDir ( ) { String random = String . valueOf ( RANDOM . nextLong ( ) ) ; File dir = tmpFile ( "dir" + random ) ; assureDirExists ( dir ) ; return dir ; }
return a temporary directory with randomly - generated number added to name to uniquely identifier it .
