1 /*
   2  * Copyright (c) 2003, 2015, 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 /*
  25  * @test
  26  * @bug     4858522
  27  * @summary Basic unit test of OperatingSystemMXBean.getFreePhysicalMemorySize()
  28  * @author  Steve Bohne
  29  */
  30 
  31 /*
  32  * This test is just a sanity check and does not check for the correct
  33  * value.  The correct value should be checked manually:
  34  * Solaris:
  35  *   1. In a shell, enter the command: "sar -r 1"
  36  *   2. The value (reported in pages) is in the "freemem" column.
  37  * Linux:
  38  *   1. In a shell, enter the command: "cat /proc/meminfo"
  39  *   2. The value (reported in bytes) is in "Mem" entry, "free" column.
  40  * Windows NT/XP/2000:
  41  *   1. Hit Ctrl-Alt-Delete, select Task Manager, go to Performance tab.
  42  *   2. The value (reported in Kbytes) is in the entry "Available" in the
  43  *      "Physical Memory" box.
  44  * Windows 98/ME:
  45  *   1. Run Start->Programs->Accessories->System Tools->System Information.
  46  *   2. Use the "XXXMB RAM" and "XX% system resources free" to determine free
  47  *      physical memory.
  48  */
  49 
  50 import com.sun.management.OperatingSystemMXBean;
  51 import java.lang.management.*;
  52 
  53 public class GetFreePhysicalMemorySize {
  54 
  55     private static OperatingSystemMXBean mbean =
  56         (com.sun.management.OperatingSystemMXBean)
  57         ManagementFactory.getOperatingSystemMXBean();
  58 
  59     // Careful with these values.
  60     private static final long MIN_SIZE_FOR_PASS = 1;
  61     // Max size for pass dynamically determined below.
  62     private static long       max_size_for_pass = Long.MAX_VALUE;
  63 
  64     private static boolean trace = false;
  65 
  66     public static void main(String args[]) throws Exception {
  67         if (args.length > 0 && args[0].equals("trace")) {
  68             trace = true;
  69         }
  70 
  71         long max_size = mbean.getTotalPhysicalMemorySize();
  72         if (max_size > 0) {
  73             max_size_for_pass = max_size;
  74         }
  75 
  76         long size = mbean.getFreePhysicalMemorySize();
  77 
  78         if (trace) {
  79             System.out.println("Free physical memory size in bytes: " + size);
  80         }
  81 
  82         if (size < MIN_SIZE_FOR_PASS || size > max_size_for_pass) {
  83             throw new RuntimeException("Free physical memory size " +
  84                                        "illegal value: " + size + " bytes " +
  85                                        "(MIN = " + MIN_SIZE_FOR_PASS + "; " +
  86                                        "MAX = " + max_size_for_pass + ")");
  87         }
  88 
  89         System.out.println("Test passed.");
  90     }
  91 }