1 /*
   2  * Copyright (c) 2014, Google Inc. All rights reserved.
   3  * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  */
  24 
  25 /*
  26  * @test
  27  * @bug 8055949
  28  * @summary Check that we can write (almost) Integer.MAX_VALUE bytes
  29  *          to a ByteArrayOutputStream.
  30  * @requires os.maxMemory > 8G
  31  * @run main/timeout=1800/othervm -Xmx8g MaxCapacity
  32  * @author Martin Buchholz
  33  */
  34 import java.io.ByteArrayOutputStream;
  35 
  36 public class MaxCapacity {
  37     public static void main(String[] args) {
  38         long maxHeap = Runtime.getRuntime().maxMemory();
  39         if (maxHeap < 3L * Integer.MAX_VALUE) {
  40             System.out.printf("Skipping test; max memory %sM too small%n",
  41                               maxHeap/(1024*1024));
  42             return;
  43         }
  44         ByteArrayOutputStream baos = new ByteArrayOutputStream();
  45         for (long n = 0; ; n++) {
  46             try {
  47                 baos.write((byte)'x');
  48             } catch (Throwable t) {
  49                 // check data integrity while we're here
  50                 byte[] bytes = baos.toByteArray();
  51                 if (bytes.length != n)
  52                     throw new AssertionError("wrong length");
  53                 if (bytes[0] != 'x' ||
  54                     bytes[bytes.length - 1] != 'x')
  55                     throw new AssertionError("wrong contents");
  56 
  57                 long gap = Integer.MAX_VALUE - n;
  58                 System.out.printf("gap=%dM %d%n", gap/(1024*1024), gap);
  59                 if (gap > 1024)
  60                     throw t;
  61                 // t.printStackTrace();
  62                 break;
  63             }
  64         }
  65     }
  66 }