1 /*
   2  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /* @test
  25  * @bug 4802340
  26  * @summary Testing force(), load() isLoaded() of zero len MBB
  27  * @run main/othervm ZeroMap

  28  */
  29 
  30 import java.io.*;
  31 import java.nio.*;
  32 import java.util.*;
  33 import java.nio.channels.*;
  34 
  35 public class ZeroMap {
  36     public static void main(String[] args) throws Exception {
  37         Random random = new Random();
  38         long filesize = random.nextInt(1024*1024);
  39         int cut = random.nextInt((int)filesize);
  40         File file = File.createTempFile("Blah", null);
  41         file.deleteOnExit();
  42         try (RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
  43             raf.setLength(filesize);
  44             FileChannel fc = raf.getChannel();
  45             MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_WRITE, cut, 0);
  46             mbb.force();
  47             mbb.load();
  48             mbb.isLoaded();
  49        }
  50 
  51         // improve chance that mapped buffer will be unmapped
  52         System.gc();
  53         Thread.sleep(500);
  54     }
  55 }
--- EOF ---