1 /*
   2  * Copyright (c) 2003, 2020, 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
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  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
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  23 
  24 /* @test
  25  * @requires os.family == "Linux"
  26  * @bug 4863423
  27  * @summary Test Util caching policy
  28  */
  29 
  30 import java.io.*;
  31 import java.nio.*;
  32 import java.nio.channels.*;
  33 
  34 public class BigReadWrite {
  35 
  36     static int testSize = 15;
  37 
  38     public static void main(String[] args) throws Exception {
  39         FileOutputStream fos = new FileOutputStream("/dev/zero");
  40         FileChannel fc = fos.getChannel();
  41 
  42         // Three small writes to fill up the Util cache
  43         ByteBuffer buf = ByteBuffer.allocate(900);
  44         fc.write(buf);
  45         buf = ByteBuffer.allocate(950);
  46         fc.write(buf);
  47         buf = ByteBuffer.allocate(975);
  48         fc.write(buf);
  49         buf = ByteBuffer.allocate(4419000);
  50 
  51         // Now initiate large write to create larger direct buffers
  52         long iterations = 0;
  53         while (iterations < 50) {
  54             fc.write(buf);
  55             buf.rewind();
  56             iterations++;
  57         }
  58         // Clean up
  59         fc.close();
  60     }
  61 }