Force.java revision 11822:110f7f35760f 
1/*
2 * Copyright (c) 2002, 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 4625907
26 * @summary Testing force()
27 * @run main/othervm Force
28 * @key randomness
29 */
30
31import java.io.*;
32import java.nio.*;
33import java.util.*;
34import java.nio.channels.*;
35
36public class Force {
37    public static void main(String[] args) throws Exception {
38        Random random = new Random();
39        long filesize = random.nextInt(3*1024*1024);
40        int cut = random.nextInt((int)filesize);
41        File file = File.createTempFile("Blah", null);
42        file.deleteOnExit();
43        try (RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
44            raf.setLength(filesize);
45            FileChannel fc = raf.getChannel();
46            MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_WRITE, cut, filesize-cut);
47            mbb.force();
48        }
49
50        // improve chance that mapped buffer will be unmapped
51        System.gc();
52        Thread.sleep(500);
53    }
54}
55