code: static private File[] finder( String dirName, final String suffix){
  		if (null == dirName || null == suffix) {
  			return null;
  		}
  
  		final File dir = new File(dirName);
  		return dir.listFiles(new FilenameFilter() {
  			@Override
  			public boolean accept(File dir, String filename)
  			{ return filename.endsWith(suffix); }
  		} );
  	}
docs: Return File(s) in dirName that match suffix.
  @param dirName
  @param suffix
  @return