1 /* 2 * Copyright (c) 2007, 2016, 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 6606598 7024172 26 * @summary Unit test for java.lang.management.BufferPoolMXBean 27 * @modules jdk.management 28 * @run main/othervm Basic 29 * @key randomness 30 */ 31 32 import java.nio.ByteBuffer; 33 import java.nio.MappedByteBuffer; 34 import java.nio.file.Path; 35 import java.nio.file.Files; 36 import static java.nio.file.StandardOpenOption.*; 37 import java.nio.channels.FileChannel; 38 import java.lang.management.BufferPoolMXBean; 39 import java.lang.management.ManagementFactory; 40 import javax.management.MBeanServer; 41 import javax.management.ObjectName; 42 import java.lang.ref.WeakReference; 43 import java.util.*; 44 45 public class Basic { 46 47 // static fields to ensure buffers aren't GC'ed 48 static List<ByteBuffer> buffers; 49 static MappedByteBuffer mbb; 50 51 // check counters 52 static void check(List<BufferPoolMXBean> pools, 53 int minBufferCount, 54 long minTotalCapacity) 55 { 56 int bufferCount = 0; 57 long totalCap = 0; 58 long totalMem = 0; 59 for (BufferPoolMXBean pool: pools) { 60 bufferCount += pool.getCount(); 61 totalCap += pool.getTotalCapacity(); 62 totalMem += pool.getMemoryUsed(); 63 } 64 if (bufferCount < minBufferCount) 65 throw new RuntimeException("Count less than expected"); 66 if (totalMem < minTotalCapacity) 67 throw new RuntimeException("Memory usage less than expected"); 68 if (totalCap < minTotalCapacity) 69 throw new RuntimeException("Total capacity less than expected"); 70 } 71 72 public static void main(String[] args) throws Exception { 73 Random rand = new Random(); 74 75 // allocate a few direct buffers 76 int bufferCount = 5 + rand.nextInt(20); 77 buffers = new ArrayList<ByteBuffer>(bufferCount); 78 long totalCapacity = 0L; 79 for (int i=0; i<bufferCount; i++) { 80 int cap = 1024 + rand.nextInt(4096); 81 buffers.add( ByteBuffer.allocateDirect(cap) ); 82 totalCapacity += cap; 83 } 84 85 // create a mapped buffer 86 Path tmpfile = Files.createTempFile("blah", null); 87 tmpfile.toFile().deleteOnExit(); 88 try (FileChannel fc = FileChannel.open(tmpfile, READ, WRITE)) { 89 mbb = fc.map(FileChannel.MapMode.READ_WRITE, 10, 100); 90 bufferCount++; 91 totalCapacity += mbb.capacity(); 92 } 93 94 // use platform MXBeans directly 95 List<BufferPoolMXBean> pools = 96 ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class); 97 check(pools, bufferCount, totalCapacity); 98 99 // use MBeanServer 100 MBeanServer server = ManagementFactory.getPlatformMBeanServer(); 101 Set<ObjectName> mbeans = server.queryNames( 102 new ObjectName("java.nio:type=BufferPool,*"), null); 103 pools = new ArrayList<BufferPoolMXBean>(); 104 for (ObjectName name: mbeans) { 105 BufferPoolMXBean pool = ManagementFactory 106 .newPlatformMXBeanProxy(server, name.toString(), BufferPoolMXBean.class); 107 pools.add(pool); 108 } 109 check(pools, bufferCount, totalCapacity); 110 111 // attempt to unmap mapped buffer 112 WeakReference<MappedByteBuffer> ref = new WeakReference<>(mbb); 113 mbb = null; 114 do { 115 System.gc(); 116 Thread.sleep(250); 117 } while (ref.get() != null); 118 } 119 }