Java tutorial
/* * @(#)VerboseGC.java 1.4 05/11/17 * * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Sun Microsystems, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * @(#)VerboseGC.java 1.4 05/11/17 */ import static java.lang.management.ManagementFactory.GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE; import static java.lang.management.ManagementFactory.MEMORY_MXBEAN_NAME; import static java.lang.management.ManagementFactory.MEMORY_POOL_MXBEAN_DOMAIN_TYPE; import static java.lang.management.ManagementFactory.RUNTIME_MXBEAN_NAME; import static java.lang.management.ManagementFactory.getGarbageCollectorMXBeans; import static java.lang.management.ManagementFactory.getMemoryMXBean; import static java.lang.management.ManagementFactory.getMemoryPoolMXBeans; import static java.lang.management.ManagementFactory.getRuntimeMXBean; import static java.lang.management.ManagementFactory.newPlatformMXBeanProxy; import java.io.IOException; import java.lang.management.GarbageCollectorMXBean; import java.lang.management.MemoryMXBean; import java.lang.management.MemoryPoolMXBean; import java.lang.management.MemoryUsage; import java.lang.management.RuntimeMXBean; import java.net.MalformedURLException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Set; import javax.management.MBeanServerConnection; import javax.management.MalformedObjectNameException; import javax.management.ObjectName; import javax.management.remote.JMXConnector; import javax.management.remote.JMXConnectorFactory; import javax.management.remote.JMXServiceURL; /** * This VerboseGC class demonstrates the capability to get the garbage * collection statistics and memory usage remotely. */ public class VerboseGC { private MBeanServerConnection server; private JMXConnector jmxc; public VerboseGC(String hostname, int port) { System.out.println("Connecting to " + hostname + ":" + port); // Create an RMI connector client and connect it to // the RMI connector server String urlPath = "/jndi/rmi://" + hostname + ":" + port + "/jmxrmi"; connect(urlPath); } public void dump(long interval, long samples) { try { PrintGCStat pstat = new PrintGCStat(server); for (int i = 0; i < samples; i++) { pstat.printVerboseGc(); try { Thread.sleep(interval); } catch (InterruptedException e) { System.exit(1); } } } catch (IOException e) { System.err.println("\nCommunication error: " + e.getMessage()); System.exit(1); } } /** * Connect to a JMX agent of a given URL. */ private void connect(String urlPath) { try { JMXServiceURL url = new JMXServiceURL("rmi", "", 0, urlPath); this.jmxc = JMXConnectorFactory.connect(url); this.server = jmxc.getMBeanServerConnection(); } catch (MalformedURLException e) { // should not reach here } catch (IOException e) { System.err.println("\nCommunication error: " + e.getMessage()); System.exit(1); } } public static void main(String[] args) { if (args.length < 1) { usage(); } String hostname = ""; int port = -1; long interval = 5000; // default is 5 second interval long mins = 5; for (int argIndex = 0; argIndex < args.length; argIndex++) { String arg = args[argIndex]; if (args[argIndex].startsWith("-")) { if (arg.equals("-h") || arg.equals("-help") || arg.equals("-?")) { usage(); } else if (arg.startsWith("-interval=")) { try { interval = Integer.parseInt(arg.substring(10)) * 1000; } catch (NumberFormatException ex) { usage(); } } else if (arg.startsWith("-duration=")) { try { mins = Integer.parseInt(arg.substring(10)); } catch (NumberFormatException ex) { usage(); } } else { // Unknown switch System.err.println("Unrecognized option: " + arg); usage(); } } else { String[] arg2 = arg.split(":"); if (arg2.length != 2) { usage(); } hostname = arg2[0]; try { port = Integer.parseInt(arg2[1]); } catch (NumberFormatException x) { usage(); } if (port < 0) { usage(); } } } // get full thread dump and perform deadlock detection VerboseGC vgc = new VerboseGC(hostname, port); long samples = (mins * 60 * 1000) / interval; vgc.dump(interval, samples); } private static void usage() { System.out.print("Usage: java VerboseGC <hostname>:<port> "); System.out.println(" [-interval=seconds] [-duration=minutes]"); } } /* * @(#)PrintGCStat.java 1.4 05/11/17 * * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Sun Microsystems, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * This software is provided "AS IS," without a warranty of any kind. ALL * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS * LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A * RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. * IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT * OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR * PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS * BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended for * use in the design, construction, operation or maintenance of any nuclear * facility. */ /* * @(#)PrintGCStat.java 1.4 05/11/17 */ /** * Example of using the java.lang.management API to monitor the memory usage and * garbage collection statistics. * * @author Mandy Chung * @version %% 11/17/05 */ class PrintGCStat { private RuntimeMXBean rmbean; private MemoryMXBean mmbean; private List<MemoryPoolMXBean> pools; private List<GarbageCollectorMXBean> gcmbeans; /** * Constructs a PrintGCStat object to monitor a remote JVM. */ public PrintGCStat(MBeanServerConnection server) throws IOException { // Create the platform mxbean proxies this.rmbean = newPlatformMXBeanProxy(server, RUNTIME_MXBEAN_NAME, RuntimeMXBean.class); this.mmbean = newPlatformMXBeanProxy(server, MEMORY_MXBEAN_NAME, MemoryMXBean.class); ObjectName poolName = null; ObjectName gcName = null; try { poolName = new ObjectName(MEMORY_POOL_MXBEAN_DOMAIN_TYPE + ",*"); gcName = new ObjectName(GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE + ",*"); } catch (MalformedObjectNameException e) { // should not reach here assert (false); } Set mbeans = server.queryNames(poolName, null); if (mbeans != null) { pools = new ArrayList<MemoryPoolMXBean>(); Iterator iterator = mbeans.iterator(); while (iterator.hasNext()) { ObjectName objName = (ObjectName) iterator.next(); MemoryPoolMXBean p = newPlatformMXBeanProxy(server, objName.getCanonicalName(), MemoryPoolMXBean.class); pools.add(p); } } mbeans = server.queryNames(gcName, null); if (mbeans != null) { gcmbeans = new ArrayList<GarbageCollectorMXBean>(); Iterator iterator = mbeans.iterator(); while (iterator.hasNext()) { ObjectName objName = (ObjectName) iterator.next(); GarbageCollectorMXBean gc = newPlatformMXBeanProxy(server, objName.getCanonicalName(), GarbageCollectorMXBean.class); gcmbeans.add(gc); } } } /** * Constructs a PrintGCStat object to monitor the local JVM. */ public PrintGCStat() { // Obtain the platform mxbean instances for the running JVM. this.rmbean = getRuntimeMXBean(); this.mmbean = getMemoryMXBean(); this.pools = getMemoryPoolMXBeans(); this.gcmbeans = getGarbageCollectorMXBeans(); } /** * Prints the verbose GC log to System.out to list the memory usage of all * memory pools as well as the GC statistics. */ public void printVerboseGc() { System.out.print("Uptime: " + formatMillis(rmbean.getUptime())); for (GarbageCollectorMXBean gc : gcmbeans) { System.out.print(" [" + gc.getName() + ": "); System.out.print("Count=" + gc.getCollectionCount()); System.out.print(" GCTime=" + formatMillis(gc.getCollectionTime())); System.out.print("]"); } System.out.println(); for (MemoryPoolMXBean p : pools) { System.out.print(" [" + p.getName() + ":"); MemoryUsage u = p.getUsage(); System.out.print(" Used=" + formatBytes(u.getUsed())); System.out.print(" Committed=" + formatBytes(u.getCommitted())); System.out.println("]"); } } private String formatMillis(long ms) { return String.format("%.4fsec", ms / (double) 1000); } private String formatBytes(long bytes) { long kb = bytes; if (bytes > 0) { kb = bytes / 1024; } return kb + "K"; } }