Java tutorial
//package com.java2s; import java.io.File; import java.io.IOException; public class Main { /** * Deletes the contents of {@code dir}. Throws an IOException if any file * could not be deleted, or if {@code dir} is not a readable directory. */ public static void deleteContents(File dir) throws IOException { File[] files = dir.listFiles(); if (files == null) { throw new IOException("not a readable directory: " + dir); } for (File file : files) { if (file.isDirectory()) { deleteContents(file); } if (!file.delete()) { throw new IOException("failed to delete file: " + file); } } } }