https://github.com/google/guava/guava: Guava is a suite of core and expanded libraries that include utility classes, google's collections, io classes, and much much more. 
/*
 * Copyright (C) 2014 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.io;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.j2objc.annotations.J2ObjCIncompatible;
import java.nio.file.SecureDirectoryStream;


Options for use with recursive delete methods (MoreFiles.deleteRecursively and MoreFiles.deleteDirectoryContents). 
Author:Colin Decker
Since:21.0
/**
 * Options for use with recursive delete methods ({@link MoreFiles#deleteRecursively} and {@link
 * MoreFiles#deleteDirectoryContents}).
 *
 * @since 21.0
 * @author Colin Decker
 */
@Beta
@GwtIncompatible
@J2ObjCIncompatible // java.nio.file
public enum RecursiveDeleteOption {
  
Specifies that the recursive delete should not throw an exception when it can't be guaranteed that it can be done securely, without vulnerability to race conditions (i.e. when the file system does not support SecureDirectoryStream). 
Warning: On a file system that supports symbolic links, it is possible for an
insecure recursive delete to delete files and directories that are outside the directory being deleted. This can happen if, after checking that a file is a directory (and not a symbolic link), that directory is deleted and replaced by a symbolic link to an outside directory before the call that opens the directory to read its entries. File systems that support SecureDirectoryStream do not have this vulnerability. 
/**
   * Specifies that the recursive delete should not throw an exception when it can't be guaranteed
   * that it can be done securely, without vulnerability to race conditions (i.e. when the file
   * system does not support {@link SecureDirectoryStream}).
   *
   * <p><b>Warning:</b> On a file system that supports symbolic links, it is possible for an
   * insecure recursive delete to delete files and directories that are <i>outside</i> the directory
   * being deleted. This can happen if, after checking that a file is a directory (and not a
   * symbolic link), that directory is deleted and replaced by a symbolic link to an outside
   * directory before the call that opens the directory to read its entries. File systems that
   * support {@code SecureDirectoryStream} do not have this vulnerability.
   */
  ALLOW_INSECURE
}