Java Code Examples for java.lang.management.GarbageCollectorMXBean

/**
 * Gets the garbage collection statistics from the JVM.
 *
 * @param gcMXBeans The collection of garbage collector beans.
 * @return A string denoting the number of times and total elapsed time in garbage collection.
 */
public static String getGarbageCollectorStatsAsString(List<GarbageCollectorMXBean> gcMXBeans) {
	StringBuilder bld = new StringBuilder("Garbage collector stats: ");
	
	for (GarbageCollectorMXBean bean : gcMXBeans) {
		bld.append('[').append(bean.getName()).append(", GC TIME (ms): ").append(bean.getCollectionTime());
		bld.append(", GC COUNT: ").append(bean.getCollectionCount()).append(']');
		
		bld.append(", ");
	}
	
	if (!gcMXBeans.isEmpty()) {
		bld.setLength(bld.length() - 2);
	}
	
	return bld.toString();
}
 

/**
 * 兼容Java 8和Java 10获取GC信息
 * @param haloMetricResponse
 */
private void getGcinfo(HaloMetricResponse haloMetricResponse) {
    List<GarbageCollectorMXBean> garbageCollectorMxBeans = ManagementFactory.getGarbageCollectorMXBeans();
    for (GarbageCollectorMXBean garbageCollectorMXBean : garbageCollectorMxBeans) {
        String name = beautifyGcName(garbageCollectorMXBean.getName());
        String gcCount="gc." + name + ".count";
        String gcTime="gc." + name + ".time";
        if(gcCount.equals("gc.ps_scavenge.count")||gcCount.equals("gc.g1_young_generation.count")){
            haloMetricResponse.setGcPsScavengeCount(String.valueOf(garbageCollectorMXBean.getCollectionCount()));
        }
        if(gcTime.equals("gc.ps_scavenge.time")||gcTime.equals("gc.g1_young_generation.time")){
             haloMetricResponse.setGcPsScavengeTime(String.valueOf(garbageCollectorMXBean.getCollectionTime()));
        }
        if(gcCount.equals("gc.ps_marksweep.count")||gcCount.equals("gc.g1_old_generation.count")){
            haloMetricResponse.setGcPsMarksweepCount(String.valueOf(garbageCollectorMXBean.getCollectionCount()));
        }
        if(gcTime.equals("gc.ps_marksweep.time")||gcTime.equals("gc.g1_old_generation.time")){
            haloMetricResponse.setGcPsMarksweepTime(String.valueOf(garbageCollectorMXBean.getCollectionTime()));
        }
    }
}
 

private GcStats collectGcStats() {
  //Collect GC stats by iterating over all GC beans.
  GcStats gcStats = new GcStats();

  for (GarbageCollectorMXBean garbageCollectorMXBean: this.garbageCollectorMXBeans) {
    long count = garbageCollectorMXBean.getCollectionCount();
    double duration = (double) garbageCollectorMXBean.getCollectionTime();
    if (count >= 0) {
      if (YOUNG_GC_TYPES.contains(garbageCollectorMXBean.getName())) {
        gcStats.setMinorCount(gcStats.getMinorCount() + count);
        gcStats.setMinorDuration(gcStats.getMinorDuration() + duration);
      }
      else if (OLD_GC_TYPES.contains(garbageCollectorMXBean.getName())) {
        gcStats.setMajorCount(gcStats.getMajorCount() + count);
        gcStats.setMajorDuration(gcStats.getMajorDuration() + duration);
      } else {
        gcStats.setUnknownCount(gcStats.getUnknownCount() + count);
        gcStats.setUnknownDuration(gcStats.getUnknownDuration() + duration);
      }
    }
  }
  return gcStats;
}
 

/**
 * Returns the index that immediately follows the given
 * <var>index</var>. The returned index is strictly greater
 * than the given <var>index</var>, and is contained in the table.
 * <br>If the given <var>index</var> is null, returns the first
 * index in the table.
 * <br>If there are no index after the given <var>index</var>,
 * returns null.
 **/
public SnmpOid getNext(SnmpTableHandler handler, SnmpOid index) {

    // try to call the optimized method
    if (handler instanceof SnmpCachedData)
        return getNext((SnmpCachedData)handler, index);

    // too bad - revert to non-optimized generic algorithm
    SnmpOid next = index;
    do {
        next = handler.getNext(next);
        final Object value = handler.getData(next);
        if (value instanceof GarbageCollectorMXBean)
            // That's the next! return it
            return next;
        // skip to next index...
    } while (next != null);
    return null;
}
 

/**
 * 获取GC的时间
 * 
 * @return
 */
public static String getGcTime() {
    StringBuilder sb = new StringBuilder();
    for (GarbageCollectorMXBean bean : garbageCollectorMXBeans) {
        if (sb.length() > 0) {
            sb.append("\r\n");
        }
        if (youngGenCollectorNames.contains(bean.getName())) {
            sb.append("youngGCCount:");
            sb.append(bean.getCollectionCount());
            sb.append("\r\n");
            sb.append("youngGCTime:");
            sb.append(bean.getCollectionTime());
        } else if (fullGenCollectorNames.contains(bean.getName())) {
            sb.append("fullGCCount:");
            sb.append(bean.getCollectionCount());
            sb.append("\r\n");
            sb.append("fullGCTime:");
            sb.append(bean.getCollectionTime());
        }

    }

    return sb.toString();
}
 

/**
 * Returns the index that immediately follows the given
 * <var>index</var>. The returned index is strictly greater
 * than the given <var>index</var>, and is contained in the table.
 * <br>If the given <var>index</var> is null, returns the first
 * index in the table.
 * <br>If there are no index after the given <var>index</var>,
 * returns null.
 **/
public SnmpOid getNext(SnmpTableHandler handler, SnmpOid index) {

    // try to call the optimized method
    if (handler instanceof SnmpCachedData)
        return getNext((SnmpCachedData)handler, index);

    // too bad - revert to non-optimized generic algorithm
    SnmpOid next = index;
    do {
        next = handler.getNext(next);
        final Object value = handler.getData(next);
        if (value instanceof GarbageCollectorMXBean)
            // That's the next! return it
            return next;
        // skip to next index...
    } while (next != null);
    return null;
}
 

@Override
public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
    if (!canExecute(sender, command)) {
        return true;
    }

    //java version info
    displayJavaVersion(sender);

    //java paths
    sendMessage(sender, "Java lib", System.getProperty("sun.boot.library.path", "Unknown"));
    sendMessage(sender, "Java home", System.getProperty("java.home", "Unknown"));
    sendMessage(sender, "Temp path", System.getProperty("java.io.tmpdir", "Unknown"));

    displayRuntimeInfo(sender, ManagementFactory.getRuntimeMXBean());
    displayCompilationInfo(sender, ManagementFactory.getCompilationMXBean());
    displayClassLoading(sender, ManagementFactory.getClassLoadingMXBean());

    //garbage collector
    for (GarbageCollectorMXBean collector : ManagementFactory.getGarbageCollectorMXBeans()) {
        displayCollectorStats(sender, collector);
    }

    return true;
}
 

/**
 * Check if the tenured generation are currently using a parallel GC.
 */
protected static boolean isTenuredParallelGC() {
    // Currently the only parallel GC for the tenured generation is PS MarkSweep.
    List<String> parallelGCs = Arrays.asList(new String[] { "PS MarkSweep"});
    try {
        List<GarbageCollectorMXBean> beans = ManagementFactory.getGarbageCollectorMXBeans();
        for (GarbageCollectorMXBean bean : beans) {
            if (parallelGCs.contains(bean.getName())) {
                return true;
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return false;
}
 

/**
 * 获取GC的时间
 * 
 * @return
 */
public static String getGcTime() {
    StringBuilder sb = new StringBuilder();
    for (GarbageCollectorMXBean bean : garbageCollectorMXBeans) {
        if (sb.length() > 0) {
            sb.append("\r\n");
        }
        if (youngGenCollectorNames.contains(bean.getName())) {
            sb.append("youngGCCount:");
            sb.append(bean.getCollectionCount());
            sb.append("\r\n");
            sb.append("youngGCTime:");
            sb.append(bean.getCollectionTime());
        } else if (fullGenCollectorNames.contains(bean.getName())) {
            sb.append("fullGCCount:");
            sb.append(bean.getCollectionCount());
            sb.append("\r\n");
            sb.append("fullGCTime:");
            sb.append(bean.getCollectionTime());
        }

    }

    return sb.toString();
}
 

/**
 * Returns the index that immediately follows the given
 * <var>index</var>. The returned index is strictly greater
 * than the given <var>index</var>, and is contained in the table.
 * <br>If the given <var>index</var> is null, returns the first
 * index in the table.
 * <br>If there are no index after the given <var>index</var>,
 * returns null.
 **/
public SnmpOid getNext(SnmpTableHandler handler, SnmpOid index) {

    // try to call the optimized method
    if (handler instanceof SnmpCachedData)
        return getNext((SnmpCachedData)handler, index);

    // too bad - revert to non-optimized generic algorithm
    SnmpOid next = index;
    do {
        next = handler.getNext(next);
        final Object value = handler.getData(next);
        if (value instanceof GarbageCollectorMXBean)
            // That's the next! return it
            return next;
        // skip to next index...
    } while (next != null);
    return null;
}
 

private void getGcUsage(MetricsRecordBuilder rb) {
  long count = 0;
  long timeMillis = 0;
  for (GarbageCollectorMXBean gcBean : gcBeans) {
    long c = gcBean.getCollectionCount();
    long t = gcBean.getCollectionTime();
    MetricsInfo[] gcInfo = getGcInfo(gcBean.getName());
    rb.addCounter(gcInfo[0], c).addCounter(gcInfo[1], t);
    count += c;
    timeMillis += t;
  }
  rb.addCounter(GcCount, count)
    .addCounter(GcTimeMillis, timeMillis);
  
  if (pauseMonitor != null) {
    rb.addCounter(GcNumWarnThresholdExceeded,
        pauseMonitor.getNumGcWarnThreadholdExceeded());
    rb.addCounter(GcNumInfoThresholdExceeded,
        pauseMonitor.getNumGcInfoThresholdExceeded());
    rb.addCounter(GcTotalExtraSleepTime,
        pauseMonitor.getTotalGcExtraSleepTime());
  }
}
 

public PrometheusMetrics() {

        InstrumentedAppender prometheusAppender = new InstrumentedAppender();
        //log metrics
        final LoggerContext factory = (LoggerContext) LoggerFactory.getILoggerFactory();
        final ch.qos.logback.classic.Logger root = factory.getLogger(Logger.ROOT_LOGGER_NAME);
        prometheusAppender.setContext(root.getLoggerContext());
        prometheusAppender.start();
        root.addAppender(prometheusAppender);

        //jvm (hotspot) metrics
        DefaultExports.initialize();

        //gc pause buckets
        final GcNotificationListener gcNotificationListener = new GcNotificationListener();
        for (GarbageCollectorMXBean gcBean : ManagementFactory.getGarbageCollectorMXBeans()) {
            if (gcBean instanceof NotificationEmitter) {
                ((NotificationEmitter) gcBean).addNotificationListener(gcNotificationListener, null, gcBean);
            }
        }

        log.info("Prometheus metrics set up");
    }
 

public static void register() {
    // Create an instance to receive events
    NotificationListener listener = new GarbageCollection();

    // Get the MBean server
    MBeanServer server = ManagementFactory.getPlatformMBeanServer();

    // Get the collectors
    List<GarbageCollectorMXBean> beans = ManagementFactory.getGarbageCollectorMXBeans();
    for (GarbageCollectorMXBean bean : beans) {
        // Add the listener to the garbage collector
        try {
            server.addNotificationListener(bean.getObjectName(), listener, null, bean);
        } catch (InstanceNotFoundException e) {
            // ignore
        }
    }
}
 

GcInfoBuilder(GarbageCollectorMXBean gc, String[] poolNames) {
    this.gc = gc;
    this.poolNames = poolNames;
    this.gcExtItemCount = getNumGcExtAttributes(gc);
    this.gcExtItemNames = new String[gcExtItemCount];
    this.gcExtItemDescs = new String[gcExtItemCount];
    this.gcExtItemTypes = new char[gcExtItemCount];

    // Fill the information about extension attributes
    fillGcAttributeInfo(gc, gcExtItemCount, gcExtItemNames,
                        gcExtItemTypes, gcExtItemDescs);

    // lazily build the CompositeType for the GcInfo
    // including the GC-specific extension attributes
    this.gcInfoCompositeType = null;
}
 

private void getGCStats() {
  long currentGcCount = 0;
  long currentGcDuration = 0;

  for (GarbageCollectorMXBean gc : ManagementFactory.getGarbageCollectorMXBeans()) {
    long count = gc.getCollectionCount();

    if (count >= 0) {
      currentGcCount += count;
    }

    long time = gc.getCollectionTime();

    if (time >= 0) {
      currentGcDuration += time;
    }
  }

  logger.trace("number of GCs: " + (currentGcCount - lastGcCount) + " and time spent in GCs: "
      + (currentGcDuration - lastGcDuration) + "ms");

  lastGcCount = currentGcCount;
  lastGcDuration = currentGcDuration;
}
 

static synchronized void refresh() {
    if (System.currentTimeMillis() - lastRefreshedTime <= 1000) {//1s cache
        return;
    }
    List<GarbageCollectorMXBean> garbageCollectorMxBeans = ManagementFactory
        .getGarbageCollectorMXBeans();
    for (GarbageCollectorMXBean garbageCollectorMXBean : garbageCollectorMxBeans) {
        String name = garbageCollectorMXBean.getName();
        long gccount = garbageCollectorMXBean.getCollectionCount();
        long gctime = garbageCollectorMXBean.getCollectionTime();
        GcType type = m.get(name);
        switch (type) {
            case YOUNG:
                youngGCCount = gccount;
                youngGCTime = gctime;
                break;
            case OLD:
                oldGCCount = gccount;
                oldGCTime = gctime;
                break;
        }
    }
    lastRefreshedTime = System.currentTimeMillis();
}
 

/**
 * Test of getMXBeanClass method, of class GCDataProvider.
 */
public void testGetMXBeanClass() throws Exception {
    System.out.println("getMXBeanClass");
    GCDataProvider instance = new GCDataProvider(new EmulatorMBeanServerConnection(), false);
    Class expResult = GarbageCollectorMXBean.class;
    Class result = instance.getMXBeanClass();
    assertEquals(expResult, result);
}
 

public static void main(String[] args) throws InterruptedException {
    List<GarbageCollectorMXBean> list = java.lang.management.ManagementFactory.getGarbageCollectorMXBeans();
    long collectionCountBefore = getCollectionCount(list);
    System.gc();
    long collectionCountAfter = getCollectionCount(list);
    assertLT(collectionCountBefore, collectionCountAfter);
}
 

@Override
protected Map<String, Long> getSamples() {
    Map<String, Long> samples = new HashMap<String, Long>();
    for (GarbageCollectorMXBean gcBean : allGcBeans) {
        samples.put(gcBean.getName(), gcBean.getCollectionTime());
    }
    return samples;
}
 

public static long getJVMgcCount(){
	long ret = 0; 
	
	List<GarbageCollectorMXBean> gcxs = ManagementFactory.getGarbageCollectorMXBeans();
	
	for( GarbageCollectorMXBean gcx : gcxs )
		ret += gcx.getCollectionCount();
	if( ret>0 )
		ret += jvmGCCount;
	
	return ret;
}
 

public static long getYoungGenCollectionCount(){
    long youngGCCounts = 0L;
    List<GarbageCollectorMXBean> list = ManagementFactory.getGarbageCollectorMXBeans();
    for (GarbageCollectorMXBean gmx : list) {
        if(youngGenCollectorNames.contains(gmx.getName())){
            youngGCCounts+=gmx.getCollectionCount();
        }
    }
    return youngGCCounts;
}
 

/**
 * Returns true if the given <var>index</var> is present.
 **/
public boolean contains(SnmpTableHandler handler, SnmpOid index) {
    if (handler.getData(index) instanceof GarbageCollectorMXBean)
        return true;
    // Behaves as if there was nothing at this index...
    //
    return false;
}
 

@VisibleForTesting
static ImmutableList<NotificationEmitter> findTenuredCollectorBeans(
    List<GarbageCollectorMXBean> gcBeans) {
  ImmutableList.Builder<NotificationEmitter> builder = ImmutableList.builder();
  // Examine all collectors and register for notifications from those which collect the tenured
  // space. Normally there is one such collector.
  for (GarbageCollectorMXBean gcBean : gcBeans) {
    for (String name : gcBean.getMemoryPoolNames()) {
      if (isTenuredSpace(name)) {
        builder.add((NotificationEmitter) gcBean);
      }
    }
  }
  return builder.build();
}
 

/**
 * Returns the data associated with the given index.
 * If the given index is not found, null is returned.
 * Note that returning null does not necessarily means that
 * the index was not found.
 **/
public Object  getData(SnmpTableHandler handler, SnmpOid index) {
    final Object value = handler.getData(index);
    if (value instanceof GarbageCollectorMXBean) return value;
    // Behaves as if there was nothing at this index...
    //
    return null;
}
 

/**
 * Returns true if the given <var>index</var> is present.
 **/
public boolean contains(SnmpTableHandler handler, SnmpOid index) {
    if (handler.getData(index) instanceof GarbageCollectorMXBean)
        return true;
    // Behaves as if there was nothing at this index...
    //
    return false;
}
 

private void initGC() {
  List<GarbageCollectorMXBean> l = ManagementFactory.getGarbageCollectorMXBeans();
  for (GarbageCollectorMXBean item : l) {
    if (item.isValid() && !gcMap.containsKey(item)) {
      gcMap.put(item, this.f.createStatistics(gcType, item.getName(), this.id));
    }
  }
}
 

public static CollectionSummary createFromMxBeans() {
    CollectionSummary summary = new CollectionSummary();
    List<GarbageCollectorMXBean> gcBeans = ManagementFactory.getGarbageCollectorMXBeans();
    for (int c=0; c<gcBeans.size(); c++) {
        GarbageCollectorMXBean currBean = gcBeans.get(c);
        Boolean isYoung = beanCollectorTypes.get(currBean.getName());
        assertNotNull(isYoung, "Unknown MXBean name: " + currBean.getName());
        long collectionTime = currBean.getCollectionTime() * 1000; // Convert from millis to micros.
        summary.add(currBean.getName(), isYoung.booleanValue(), currBean.getCollectionCount(), collectionTime);
    }
    return summary;
}
 

private static GarbageCollectorMXBean getCMSGCBean() {
  for (GarbageCollectorMXBean gcBean : ManagementFactory.getGarbageCollectorMXBeans()) {
    if (gcBean.getObjectName().toString().equals("java.lang:type=GarbageCollector,name=ConcurrentMarkSweep")) {
      return gcBean;
    }
  }
  return null;
}
 

private static GarbageCollectorMXBean getCMSGCBean() {
  for (GarbageCollectorMXBean gcBean : ManagementFactory.getGarbageCollectorMXBeans()) {
    if (gcBean.getObjectName().toString().equals("java.lang:type=GarbageCollector,name=ConcurrentMarkSweep")) {
      return gcBean;
    }
  }
  return null;
}
 

public static String getGCStats() {
    long totalGC = 0;
    long gcTime = 0;

    for (GarbageCollectorMXBean gc : ManagementFactory.getGarbageCollectorMXBeans()) {
        long count = gc.getCollectionCount();

        if (count >= 0) {
            totalGC += count;
        }

        long time = gc.getCollectionTime();

        if (time >= 0) {
            gcTime += time;
        }
    }

    StringBuilder sb = new StringBuilder();

    sb.append(banner("memory stats"));
    sb.append("\n- total collections: " + totalGC);
    sb.append("\n- total collection time: " + formatTime(gcTime));

    Runtime runtime = Runtime.getRuntime();
    sb.append("\n- total memory: " + $.printMem(runtime.totalMemory()));

    return sb.toString();
}