Java tutorial
//package com.java2s; import java.io.File; public class Main { public static void reNameSuffix(File dir, String oldSuffix, String newSuffix) { if (dir.isDirectory()) { File[] listFiles = dir.listFiles(); for (int i = 0; i < listFiles.length; i++) { reNameSuffix(listFiles[i], oldSuffix, newSuffix); } } else { dir.renameTo(new File(dir.getPath().replace(oldSuffix, newSuffix))); } } }