code: public static boolean isFileNewer (@Nonnull final File aFile1, @Nonnull final File aFile2)
    {
      ValueEnforcer.notNull (aFile1, "File1");
      ValueEnforcer.notNull (aFile2, "aFile2");
  
      // Compare with the same file?
      if (aFile1.equals (aFile2))
        return false;
  
      // if the first file does not exists, always false
      if (!aFile1.exists ())
        return false;
  
      // first file exists, but second file does not
      if (!aFile2.exists ())
        return true;
  
      // both exist, compare file times
      return aFile1.lastModified () > aFile2.lastModified ();
    }
docs: Returns <code>true</code> if the first file is newer than the second file.
  Returns <code>true</code> if the first file exists and the second file does
  not exist. Returns <code>false</code> if the first file is older than the
  second file. Returns <code>false</code> if the first file does not exists
  but the second does. Returns <code>false</code> if none of the files exist.
  
  @param aFile1
  First file. May not be <code>null</code>.
  @param aFile2
  Second file. May not be <code>null</code>.
  @return <code>true</code> if the first file is newer than the second file,
  <code>false</code> otherwise.