src/java.management/share/classes/sun/management/ThreadImpl.java - toolchain/jdk/jdk21 - Git at Google

 /*
  * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package sun.management;

 import java.lang.management.ManagementFactory;
 import java.lang.management.ThreadInfo;
 import java.lang.management.ThreadMXBean;
 import java.util.stream.Stream;
 import javax.management.ObjectName;
 import java.util.Arrays;
 import java.util.Objects;

 /**
  * Implementation for java.lang.management.ThreadMXBean as well as providing the
  * supporting method for com.sun.management.ThreadMXBean.
  * The supporting method for com.sun.management.ThreadMXBean can be moved to
  * jdk.management in the future.
  */

 public class ThreadImpl implements ThreadMXBean {
     private final VMManagement jvm;

     // default for thread contention monitoring is disabled.
     private boolean contentionMonitoringEnabled = false;
     private boolean cpuTimeEnabled;
     private boolean allocatedMemoryEnabled;

     /**
      * Constructor of ThreadImpl class.
      */
     protected ThreadImpl(VMManagement vm) {
         this.jvm = vm;
         this.cpuTimeEnabled = jvm.isThreadCpuTimeEnabled();
         this.allocatedMemoryEnabled = jvm.isThreadAllocatedMemoryEnabled();
     }

     @Override
     public int getThreadCount() {
         return jvm.getLiveThreadCount();
     }

     @Override
     public int getPeakThreadCount() {
         return jvm.getPeakThreadCount();
     }

     @Override
     public long getTotalStartedThreadCount() {
         return jvm.getTotalThreadCount();
     }

     @Override
     public int getDaemonThreadCount() {
         return jvm.getDaemonThreadCount();
     }

     @Override
     public boolean isThreadContentionMonitoringSupported() {
         return jvm.isThreadContentionMonitoringSupported();
     }

     @Override
     public synchronized boolean isThreadContentionMonitoringEnabled() {
        if (!isThreadContentionMonitoringSupported()) {
             throw new UnsupportedOperationException(
                 "Thread contention monitoring is not supported.");
         }
         return contentionMonitoringEnabled;
     }

     @Override
     public boolean isThreadCpuTimeSupported() {
         return jvm.isOtherThreadCpuTimeSupported();
     }

     @Override
     public boolean isCurrentThreadCpuTimeSupported() {
         return jvm.isCurrentThreadCpuTimeSupported();
     }

     protected boolean isThreadAllocatedMemorySupported() {
         return jvm.isThreadAllocatedMemorySupported();
     }

     @Override
     public boolean isThreadCpuTimeEnabled() {
         if (!isThreadCpuTimeSupported() &&
             !isCurrentThreadCpuTimeSupported()) {
             throw new UnsupportedOperationException(
                 "Thread CPU time measurement is not supported");
         }
         return cpuTimeEnabled;
     }

     private void ensureThreadAllocatedMemorySupported() {
         if (!isThreadAllocatedMemorySupported()) {
             throw new UnsupportedOperationException(
                 "Thread allocated memory measurement is not supported.");
         }
     }

     protected boolean isThreadAllocatedMemoryEnabled() {
         ensureThreadAllocatedMemorySupported();
         return allocatedMemoryEnabled;
     }

     @Override
     public long[] getAllThreadIds() {
         Util.checkMonitorAccess();
         Thread[] threads = getThreads();
         return threadIds(threads);
     }

     @Override
     public ThreadInfo getThreadInfo(long id) {
         return getThreadInfo(id, 0);
     }

     @Override
     public ThreadInfo getThreadInfo(long id, int maxDepth) {
         long[] ids = new long[] { id };
         return getThreadInfo(ids, maxDepth)[0];
     }

     @Override
     public ThreadInfo[] getThreadInfo(long[] ids) {
         return getThreadInfo(ids, 0);
     }

     private void verifyThreadId(long id) {
         if (id <= 0) {
             throw new IllegalArgumentException(
                 "Invalid thread ID parameter: " + id);
         }
     }

     private void verifyThreadIds(long[] ids) {
         Objects.requireNonNull(ids);

         for (int i = 0; i < ids.length; i++) {
             verifyThreadId(ids[i]);
         }
     }

     @Override
     public ThreadInfo[] getThreadInfo(long[] ids, int maxDepth) {
         verifyThreadIds(ids);

         if (maxDepth < 0) {
             throw new IllegalArgumentException(
                 "Invalid maxDepth parameter: " + maxDepth);
         }

         // ids has been verified to be non-null
         // an empty array of ids should return an empty array of ThreadInfos
         if (ids.length == 0) return new ThreadInfo[0];

         Util.checkMonitorAccess();

         ThreadInfo[] infos = new ThreadInfo[ids.length]; // nulls
         if (maxDepth == Integer.MAX_VALUE) {
             getThreadInfo1(ids, -1, infos);
         } else {
             getThreadInfo1(ids, maxDepth, infos);
         }
         return infos;
     }

     @Override
     public void setThreadContentionMonitoringEnabled(boolean enable) {
         if (!isThreadContentionMonitoringSupported()) {
             throw new UnsupportedOperationException(
                 "Thread contention monitoring is not supported");
         }

         Util.checkControlAccess();

         synchronized (this) {
             if (contentionMonitoringEnabled != enable) {
                 if (enable) {
                     // if reeabled, reset contention time statistics
                     // for all threads
                     resetContentionTimes0(0);
                 }

                 // update the VM of the state change
                 setThreadContentionMonitoringEnabled0(enable);

                 contentionMonitoringEnabled = enable;
             }
         }
     }

     private boolean verifyCurrentThreadCpuTime() {
         if (!isCurrentThreadCpuTimeSupported()) {
             throw new UnsupportedOperationException(
                 "Current thread CPU time measurement is not supported.");
         }
         return isThreadCpuTimeEnabled();
     }

     @Override
     public long getCurrentThreadCpuTime() {
         if (verifyCurrentThreadCpuTime() && !Thread.currentThread().isVirtual()) {
             return getThreadTotalCpuTime0(0);
         }
         return -1;
     }

     @Override
     public long getThreadCpuTime(long id) {
         long[] ids = new long[1];
         ids[0] = id;
         final long[] times = getThreadCpuTime(ids);
         return times[0];
     }

     private boolean verifyThreadCpuTime(long[] ids) {
         verifyThreadIds(ids);

         // check if Thread CPU time measurement is supported.
         if (!isThreadCpuTimeSupported() &&
             !isCurrentThreadCpuTimeSupported()) {
             throw new UnsupportedOperationException(
                 "Thread CPU time measurement is not supported.");
         }

         if (!isThreadCpuTimeSupported()) {
             // support current thread only
             for (int i = 0; i < ids.length; i++) {
                 if (ids[i] != Thread.currentThread().threadId()) {
                     throw new UnsupportedOperationException(
                         "Thread CPU time measurement is only supported" +
                         " for the current thread.");
                 }
             }
         }

         return isThreadCpuTimeEnabled();
     }

     protected long[] getThreadCpuTime(long[] ids) {
         boolean verified = verifyThreadCpuTime(ids);

         int length = ids.length;
         long[] times = new long[length];
         java.util.Arrays.fill(times, -1);

         if (verified) {
             if (length == 1) {
                 long id = ids[0];
                 Thread thread = Thread.currentThread();
                 if (id == thread.threadId()) {
                     times[0] = thread.isVirtual() ? -1L : getThreadTotalCpuTime0(0);
                 } else {
                     times[0] = getThreadTotalCpuTime0(id);
                 }
             } else {
                 getThreadTotalCpuTime1(ids, times);
             }
         }
         return times;
     }

     @Override
     public long getCurrentThreadUserTime() {
         if (verifyCurrentThreadCpuTime() && !Thread.currentThread().isVirtual()) {
             return getThreadUserCpuTime0(0);
         }
         return -1;
     }

     @Override
     public long getThreadUserTime(long id) {
         long[] ids = new long[1];
         ids[0] = id;
         final long[] times = getThreadUserTime(ids);
         return times[0];
     }

     protected long[] getThreadUserTime(long[] ids) {
         boolean verified = verifyThreadCpuTime(ids);

         int length = ids.length;
         long[] times = new long[length];
         java.util.Arrays.fill(times, -1);

         if (verified) {
             if (length == 1) {
                 long id = ids[0];
                 Thread thread = Thread.currentThread();
                 if (id == thread.threadId()) {
                     times[0] = thread.isVirtual() ? -1L : getThreadTotalCpuTime0(0);
                 } else {
                     times[0] = getThreadUserCpuTime0(id);
                 }
             } else {
                 getThreadUserCpuTime1(ids, times);
             }
         }
         return times;
     }

     @Override
     public void setThreadCpuTimeEnabled(boolean enable) {
         if (!isThreadCpuTimeSupported() &&
             !isCurrentThreadCpuTimeSupported()) {
             throw new UnsupportedOperationException(
                 "Thread CPU time measurement is not supported");
         }

         Util.checkControlAccess();
         synchronized (this) {
             if (cpuTimeEnabled != enable) {
                 // notify VM of the state change
                 setThreadCpuTimeEnabled0(enable);
                 cpuTimeEnabled = enable;
             }
         }
     }

     protected long getTotalThreadAllocatedBytes() {
         if (isThreadAllocatedMemoryEnabled()) {
             return getTotalThreadAllocatedMemory();
         }
         return -1;
     }

     protected long getCurrentThreadAllocatedBytes() {
         if (isThreadAllocatedMemoryEnabled() && !Thread.currentThread().isVirtual()) {
             return getThreadAllocatedMemory0(0);
         }
         return -1;
     }

     private boolean verifyThreadAllocatedMemory(long id) {
         verifyThreadId(id);
         return isThreadAllocatedMemoryEnabled();
     }

     protected long getThreadAllocatedBytes(long id) {
         boolean verified = verifyThreadAllocatedMemory(id);
         if (verified) {
             Thread thread = Thread.currentThread();
             if (id == thread.threadId()) {
                 return thread.isVirtual() ? -1L : getThreadAllocatedMemory0(0);
             } else {
                 return getThreadAllocatedMemory0(id);
             }
         }
         return -1;
     }

     private boolean verifyThreadAllocatedMemory(long[] ids) {
         verifyThreadIds(ids);
         return isThreadAllocatedMemoryEnabled();
     }

     protected long[] getThreadAllocatedBytes(long[] ids) {
         Objects.requireNonNull(ids);

         if (ids.length == 1) {
             long size = getThreadAllocatedBytes(ids[0]);
             return new long[] { size };
         }

         boolean verified = verifyThreadAllocatedMemory(ids);

         long[] sizes = new long[ids.length];
         java.util.Arrays.fill(sizes, -1);

         if (verified) {
             getThreadAllocatedMemory1(ids, sizes);
         }
         return sizes;
     }

     protected void setThreadAllocatedMemoryEnabled(boolean enable) {
         ensureThreadAllocatedMemorySupported();

         Util.checkControlAccess();
         synchronized (this) {
             if (allocatedMemoryEnabled != enable) {
                 // notify VM of the state change
                 setThreadAllocatedMemoryEnabled0(enable);
                 allocatedMemoryEnabled = enable;
             }
         }
     }

     /**
      * Returns an array of thread identifiers for the threads in the given
      * array. Returns {@code null} if {@code threads} is null or the array
      * of threads is empty.
      */
     private long[] threadsToIds(Thread[] threads) {
         if (threads != null && threads.length > 0) {
             return threadIds(threads);
         } else {
             return null;
         }
     }

     @Override
     public long[] findMonitorDeadlockedThreads() {
         Util.checkMonitorAccess();
         Thread[] threads = findMonitorDeadlockedThreads0();
         return threadsToIds(threads);
     }

     @Override
     public long[] findDeadlockedThreads() {
         if (!isSynchronizerUsageSupported()) {
             throw new UnsupportedOperationException(
                 "Monitoring of Synchronizer Usage is not supported.");
         }

         Util.checkMonitorAccess();

         Thread[] threads = findDeadlockedThreads0();
         return threadsToIds(threads);
     }

     @Override
     public void resetPeakThreadCount() {
         Util.checkControlAccess();
         resetPeakThreadCount0();
     }

     @Override
     public boolean isObjectMonitorUsageSupported() {
         return jvm.isObjectMonitorUsageSupported();
     }

     @Override
     public boolean isSynchronizerUsageSupported() {
         return jvm.isSynchronizerUsageSupported();
     }

     private void verifyDumpThreads(boolean lockedMonitors,
                                    boolean lockedSynchronizers) {
         if (lockedMonitors && !isObjectMonitorUsageSupported()) {
             throw new UnsupportedOperationException(
                 "Monitoring of Object Monitor Usage is not supported.");
         }

         if (lockedSynchronizers && !isSynchronizerUsageSupported()) {
             throw new UnsupportedOperationException(
                 "Monitoring of Synchronizer Usage is not supported.");
         }

         Util.checkMonitorAccess();
     }

     @Override
     public ThreadInfo[] getThreadInfo(long[] ids,
                                       boolean lockedMonitors,
                                       boolean lockedSynchronizers) {
         return dumpThreads0(ids, lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE);
     }

     @Override
     public ThreadInfo[] getThreadInfo(long[] ids,
                                       boolean lockedMonitors,
                                       boolean lockedSynchronizers,
                                       int maxDepth) {
         if (maxDepth < 0) {
             throw new IllegalArgumentException(
                     "Invalid maxDepth parameter: " + maxDepth);
         }
         verifyThreadIds(ids);
         // ids has been verified to be non-null
         // an empty array of ids should return an empty array of ThreadInfos
         if (ids.length == 0) return new ThreadInfo[0];

         verifyDumpThreads(lockedMonitors, lockedSynchronizers);
         return dumpThreads0(ids, lockedMonitors, lockedSynchronizers, maxDepth);
     }

     @Override
     public ThreadInfo[] dumpAllThreads(boolean lockedMonitors,
                                        boolean lockedSynchronizers) {
         return dumpAllThreads(lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE);
     }

     @Override
     public ThreadInfo[] dumpAllThreads(boolean lockedMonitors,
                                        boolean lockedSynchronizers,
                                        int maxDepth) {
         if (maxDepth < 0) {
             throw new IllegalArgumentException(
                     "Invalid maxDepth parameter: " + maxDepth);
         }
         verifyDumpThreads(lockedMonitors, lockedSynchronizers);
         ThreadInfo[] infos = dumpThreads0(null, lockedMonitors, lockedSynchronizers, maxDepth);
         return Arrays.stream(infos)
                 .filter(ti -> ti != null)
                 .toArray(ThreadInfo[]::new);
     }

     // VM support where maxDepth == -1 to request entire stack dump
     private static native Thread[] getThreads();
     private static native void getThreadInfo1(long[] ids,
                                               int maxDepth,
                                               ThreadInfo[] result);
     private static native long getThreadTotalCpuTime0(long id);
     private static native void getThreadTotalCpuTime1(long[] ids, long[] result);
     private static native long getThreadUserCpuTime0(long id);
     private static native void getThreadUserCpuTime1(long[] ids, long[] result);
     private static native long getThreadAllocatedMemory0(long id);
     private static native void getThreadAllocatedMemory1(long[] ids, long[] result);
     private static native long getTotalThreadAllocatedMemory();
     private static native void setThreadCpuTimeEnabled0(boolean enable);
     private static native void setThreadAllocatedMemoryEnabled0(boolean enable);
     private static native void setThreadContentionMonitoringEnabled0(boolean enable);
     private static native Thread[] findMonitorDeadlockedThreads0();
     private static native Thread[] findDeadlockedThreads0();
     private static native void resetPeakThreadCount0();
     private static native ThreadInfo[] dumpThreads0(long[] ids,
                                                     boolean lockedMonitors,
                                                     boolean lockedSynchronizers,
                                                     int maxDepth);

     // tid == 0 to reset contention times for all threads
     private static native void resetContentionTimes0(long tid);

     @Override
     public ObjectName getObjectName() {
         return Util.newObjectName(ManagementFactory.THREAD_MXBEAN_NAME);
     }

     /**
      * Returns the thread identifiers of the threads in the given array.
      */
     private static long[] threadIds(Thread[] threads) {
         return Stream.of(threads)
                 .mapToLong(Thread::threadId)
                 .toArray();
     }
 }
	/*
	* Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.management;

	import java.lang.management.ManagementFactory;
	import java.lang.management.ThreadInfo;
	import java.lang.management.ThreadMXBean;
	import java.util.stream.Stream;
	import javax.management.ObjectName;
	import java.util.Arrays;
	import java.util.Objects;

	/**
	* Implementation for java.lang.management.ThreadMXBean as well as providing the
	* supporting method for com.sun.management.ThreadMXBean.
	* The supporting method for com.sun.management.ThreadMXBean can be moved to
	* jdk.management in the future.
	*/

	public class ThreadImpl implements ThreadMXBean {
	private final VMManagement jvm;

	// default for thread contention monitoring is disabled.
	private boolean contentionMonitoringEnabled = false;
	private boolean cpuTimeEnabled;
	private boolean allocatedMemoryEnabled;

	/**
	* Constructor of ThreadImpl class.
	*/
	protected ThreadImpl(VMManagement vm) {
	this.jvm = vm;
	this.cpuTimeEnabled = jvm.isThreadCpuTimeEnabled();
	this.allocatedMemoryEnabled = jvm.isThreadAllocatedMemoryEnabled();
	}

	@Override
	public int getThreadCount() {
	return jvm.getLiveThreadCount();
	}

	@Override
	public int getPeakThreadCount() {
	return jvm.getPeakThreadCount();
	}

	@Override
	public long getTotalStartedThreadCount() {
	return jvm.getTotalThreadCount();
	}

	@Override
	public int getDaemonThreadCount() {
	return jvm.getDaemonThreadCount();
	}

	@Override
	public boolean isThreadContentionMonitoringSupported() {
	return jvm.isThreadContentionMonitoringSupported();
	}

	@Override
	public synchronized boolean isThreadContentionMonitoringEnabled() {
	if (!isThreadContentionMonitoringSupported()) {
	throw new UnsupportedOperationException(
	"Thread contention monitoring is not supported.");
	}
	return contentionMonitoringEnabled;
	}

	@Override
	public boolean isThreadCpuTimeSupported() {
	return jvm.isOtherThreadCpuTimeSupported();
	}

	@Override
	public boolean isCurrentThreadCpuTimeSupported() {
	return jvm.isCurrentThreadCpuTimeSupported();
	}

	protected boolean isThreadAllocatedMemorySupported() {
	return jvm.isThreadAllocatedMemorySupported();
	}

	@Override
	public boolean isThreadCpuTimeEnabled() {
	if (!isThreadCpuTimeSupported() &&
	!isCurrentThreadCpuTimeSupported()) {
	throw new UnsupportedOperationException(
	"Thread CPU time measurement is not supported");
	}
	return cpuTimeEnabled;
	}

	private void ensureThreadAllocatedMemorySupported() {
	if (!isThreadAllocatedMemorySupported()) {
	throw new UnsupportedOperationException(
	"Thread allocated memory measurement is not supported.");
	}
	}

	protected boolean isThreadAllocatedMemoryEnabled() {
	ensureThreadAllocatedMemorySupported();
	return allocatedMemoryEnabled;
	}

	@Override
	public long[] getAllThreadIds() {
	Util.checkMonitorAccess();
	Thread[] threads = getThreads();
	return threadIds(threads);
	}

	@Override
	public ThreadInfo getThreadInfo(long id) {
	return getThreadInfo(id, 0);
	}

	@Override
	public ThreadInfo getThreadInfo(long id, int maxDepth) {
	long[] ids = new long[] { id };
	return getThreadInfo(ids, maxDepth)[0];
	}

	@Override
	public ThreadInfo[] getThreadInfo(long[] ids) {
	return getThreadInfo(ids, 0);
	}

	private void verifyThreadId(long id) {
	if (id <= 0) {
	throw new IllegalArgumentException(
	"Invalid thread ID parameter: " + id);
	}
	}

	private void verifyThreadIds(long[] ids) {
	Objects.requireNonNull(ids);

	for (int i = 0; i < ids.length; i++) {
	verifyThreadId(ids[i]);
	}
	}

	@Override
	public ThreadInfo[] getThreadInfo(long[] ids, int maxDepth) {
	verifyThreadIds(ids);

	if (maxDepth < 0) {
	throw new IllegalArgumentException(
	"Invalid maxDepth parameter: " + maxDepth);
	}

	// ids has been verified to be non-null
	// an empty array of ids should return an empty array of ThreadInfos
	if (ids.length == 0) return new ThreadInfo[0];

	Util.checkMonitorAccess();

	ThreadInfo[] infos = new ThreadInfo[ids.length]; // nulls
	if (maxDepth == Integer.MAX_VALUE) {
	getThreadInfo1(ids, -1, infos);
	} else {
	getThreadInfo1(ids, maxDepth, infos);
	}
	return infos;
	}

	@Override
	public void setThreadContentionMonitoringEnabled(boolean enable) {
	if (!isThreadContentionMonitoringSupported()) {
	throw new UnsupportedOperationException(
	"Thread contention monitoring is not supported");
	}

	Util.checkControlAccess();

	synchronized (this) {
	if (contentionMonitoringEnabled != enable) {
	if (enable) {
	// if reeabled, reset contention time statistics
	// for all threads
	resetContentionTimes0(0);
	}

	// update the VM of the state change
	setThreadContentionMonitoringEnabled0(enable);

	contentionMonitoringEnabled = enable;
	}
	}
	}

	private boolean verifyCurrentThreadCpuTime() {
	if (!isCurrentThreadCpuTimeSupported()) {
	throw new UnsupportedOperationException(
	"Current thread CPU time measurement is not supported.");
	}
	return isThreadCpuTimeEnabled();
	}

	@Override
	public long getCurrentThreadCpuTime() {
	if (verifyCurrentThreadCpuTime() && !Thread.currentThread().isVirtual()) {
	return getThreadTotalCpuTime0(0);
	}
	return -1;
	}

	@Override
	public long getThreadCpuTime(long id) {
	long[] ids = new long[1];
	ids[0] = id;
	final long[] times = getThreadCpuTime(ids);
	return times[0];
	}

	private boolean verifyThreadCpuTime(long[] ids) {
	verifyThreadIds(ids);

	// check if Thread CPU time measurement is supported.
	if (!isThreadCpuTimeSupported() &&
	!isCurrentThreadCpuTimeSupported()) {
	throw new UnsupportedOperationException(
	"Thread CPU time measurement is not supported.");
	}

	if (!isThreadCpuTimeSupported()) {
	// support current thread only
	for (int i = 0; i < ids.length; i++) {
	if (ids[i] != Thread.currentThread().threadId()) {
	throw new UnsupportedOperationException(
	"Thread CPU time measurement is only supported" +
	" for the current thread.");
	}
	}
	}

	return isThreadCpuTimeEnabled();
	}

	protected long[] getThreadCpuTime(long[] ids) {
	boolean verified = verifyThreadCpuTime(ids);

	int length = ids.length;
	long[] times = new long[length];
	java.util.Arrays.fill(times, -1);

	if (verified) {
	if (length == 1) {
	long id = ids[0];
	Thread thread = Thread.currentThread();
	if (id == thread.threadId()) {
	times[0] = thread.isVirtual() ? -1L : getThreadTotalCpuTime0(0);
	} else {
	times[0] = getThreadTotalCpuTime0(id);
	}
	} else {
	getThreadTotalCpuTime1(ids, times);
	}
	}
	return times;
	}

	@Override
	public long getCurrentThreadUserTime() {
	if (verifyCurrentThreadCpuTime() && !Thread.currentThread().isVirtual()) {
	return getThreadUserCpuTime0(0);
	}
	return -1;
	}

	@Override
	public long getThreadUserTime(long id) {
	long[] ids = new long[1];
	ids[0] = id;
	final long[] times = getThreadUserTime(ids);
	return times[0];
	}

	protected long[] getThreadUserTime(long[] ids) {
	boolean verified = verifyThreadCpuTime(ids);

	int length = ids.length;
	long[] times = new long[length];
	java.util.Arrays.fill(times, -1);

	if (verified) {
	if (length == 1) {
	long id = ids[0];
	Thread thread = Thread.currentThread();
	if (id == thread.threadId()) {
	times[0] = thread.isVirtual() ? -1L : getThreadTotalCpuTime0(0);
	} else {
	times[0] = getThreadUserCpuTime0(id);
	}
	} else {
	getThreadUserCpuTime1(ids, times);
	}
	}
	return times;
	}

	@Override
	public void setThreadCpuTimeEnabled(boolean enable) {
	if (!isThreadCpuTimeSupported() &&
	!isCurrentThreadCpuTimeSupported()) {
	throw new UnsupportedOperationException(
	"Thread CPU time measurement is not supported");
	}

	Util.checkControlAccess();
	synchronized (this) {
	if (cpuTimeEnabled != enable) {
	// notify VM of the state change
	setThreadCpuTimeEnabled0(enable);
	cpuTimeEnabled = enable;
	}
	}
	}

	protected long getTotalThreadAllocatedBytes() {
	if (isThreadAllocatedMemoryEnabled()) {
	return getTotalThreadAllocatedMemory();
	}
	return -1;
	}

	protected long getCurrentThreadAllocatedBytes() {
	if (isThreadAllocatedMemoryEnabled() && !Thread.currentThread().isVirtual()) {
	return getThreadAllocatedMemory0(0);
	}
	return -1;
	}

	private boolean verifyThreadAllocatedMemory(long id) {
	verifyThreadId(id);
	return isThreadAllocatedMemoryEnabled();
	}

	protected long getThreadAllocatedBytes(long id) {
	boolean verified = verifyThreadAllocatedMemory(id);
	if (verified) {
	Thread thread = Thread.currentThread();
	if (id == thread.threadId()) {
	return thread.isVirtual() ? -1L : getThreadAllocatedMemory0(0);
	} else {
	return getThreadAllocatedMemory0(id);
	}
	}
	return -1;
	}

	private boolean verifyThreadAllocatedMemory(long[] ids) {
	verifyThreadIds(ids);
	return isThreadAllocatedMemoryEnabled();
	}

	protected long[] getThreadAllocatedBytes(long[] ids) {
	Objects.requireNonNull(ids);

	if (ids.length == 1) {
	long size = getThreadAllocatedBytes(ids[0]);
	return new long[] { size };
	}

	boolean verified = verifyThreadAllocatedMemory(ids);

	long[] sizes = new long[ids.length];
	java.util.Arrays.fill(sizes, -1);

	if (verified) {
	getThreadAllocatedMemory1(ids, sizes);
	}
	return sizes;
	}

	protected void setThreadAllocatedMemoryEnabled(boolean enable) {
	ensureThreadAllocatedMemorySupported();

	Util.checkControlAccess();
	synchronized (this) {
	if (allocatedMemoryEnabled != enable) {
	// notify VM of the state change
	setThreadAllocatedMemoryEnabled0(enable);
	allocatedMemoryEnabled = enable;
	}
	}
	}

	/**
	* Returns an array of thread identifiers for the threads in the given
	* array. Returns {@code null} if {@code threads} is null or the array
	* of threads is empty.
	*/
	private long[] threadsToIds(Thread[] threads) {
	if (threads != null && threads.length > 0) {
	return threadIds(threads);
	} else {
	return null;
	}
	}

	@Override
	public long[] findMonitorDeadlockedThreads() {
	Util.checkMonitorAccess();
	Thread[] threads = findMonitorDeadlockedThreads0();
	return threadsToIds(threads);
	}

	@Override
	public long[] findDeadlockedThreads() {
	if (!isSynchronizerUsageSupported()) {
	throw new UnsupportedOperationException(
	"Monitoring of Synchronizer Usage is not supported.");
	}

	Util.checkMonitorAccess();

	Thread[] threads = findDeadlockedThreads0();
	return threadsToIds(threads);
	}

	@Override
	public void resetPeakThreadCount() {
	Util.checkControlAccess();
	resetPeakThreadCount0();
	}

	@Override
	public boolean isObjectMonitorUsageSupported() {
	return jvm.isObjectMonitorUsageSupported();
	}

	@Override
	public boolean isSynchronizerUsageSupported() {
	return jvm.isSynchronizerUsageSupported();
	}

	private void verifyDumpThreads(boolean lockedMonitors,
	boolean lockedSynchronizers) {
	if (lockedMonitors && !isObjectMonitorUsageSupported()) {
	throw new UnsupportedOperationException(
	"Monitoring of Object Monitor Usage is not supported.");
	}

	if (lockedSynchronizers && !isSynchronizerUsageSupported()) {
	throw new UnsupportedOperationException(
	"Monitoring of Synchronizer Usage is not supported.");
	}

	Util.checkMonitorAccess();
	}

	@Override
	public ThreadInfo[] getThreadInfo(long[] ids,
	boolean lockedMonitors,
	boolean lockedSynchronizers) {
	return dumpThreads0(ids, lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE);
	}

	@Override
	public ThreadInfo[] getThreadInfo(long[] ids,
	boolean lockedMonitors,
	boolean lockedSynchronizers,
	int maxDepth) {
	if (maxDepth < 0) {
	throw new IllegalArgumentException(
	"Invalid maxDepth parameter: " + maxDepth);
	}
	verifyThreadIds(ids);
	// ids has been verified to be non-null
	// an empty array of ids should return an empty array of ThreadInfos
	if (ids.length == 0) return new ThreadInfo[0];

	verifyDumpThreads(lockedMonitors, lockedSynchronizers);
	return dumpThreads0(ids, lockedMonitors, lockedSynchronizers, maxDepth);
	}

	@Override
	public ThreadInfo[] dumpAllThreads(boolean lockedMonitors,
	boolean lockedSynchronizers) {
	return dumpAllThreads(lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE);
	}

	@Override
	public ThreadInfo[] dumpAllThreads(boolean lockedMonitors,
	boolean lockedSynchronizers,
	int maxDepth) {
	if (maxDepth < 0) {
	throw new IllegalArgumentException(
	"Invalid maxDepth parameter: " + maxDepth);
	}
	verifyDumpThreads(lockedMonitors, lockedSynchronizers);
	ThreadInfo[] infos = dumpThreads0(null, lockedMonitors, lockedSynchronizers, maxDepth);
	return Arrays.stream(infos)
	.filter(ti -> ti != null)
	.toArray(ThreadInfo[]::new);
	}

	// VM support where maxDepth == -1 to request entire stack dump
	private static native Thread[] getThreads();
	private static native void getThreadInfo1(long[] ids,
	int maxDepth,
	ThreadInfo[] result);
	private static native long getThreadTotalCpuTime0(long id);
	private static native void getThreadTotalCpuTime1(long[] ids, long[] result);
	private static native long getThreadUserCpuTime0(long id);
	private static native void getThreadUserCpuTime1(long[] ids, long[] result);
	private static native long getThreadAllocatedMemory0(long id);
	private static native void getThreadAllocatedMemory1(long[] ids, long[] result);
	private static native long getTotalThreadAllocatedMemory();
	private static native void setThreadCpuTimeEnabled0(boolean enable);
	private static native void setThreadAllocatedMemoryEnabled0(boolean enable);
	private static native void setThreadContentionMonitoringEnabled0(boolean enable);
	private static native Thread[] findMonitorDeadlockedThreads0();
	private static native Thread[] findDeadlockedThreads0();
	private static native void resetPeakThreadCount0();
	private static native ThreadInfo[] dumpThreads0(long[] ids,
	boolean lockedMonitors,
	boolean lockedSynchronizers,
	int maxDepth);

	// tid == 0 to reset contention times for all threads
	private static native void resetContentionTimes0(long tid);

	@Override
	public ObjectName getObjectName() {
	return Util.newObjectName(ManagementFactory.THREAD_MXBEAN_NAME);
	}

	/**
	* Returns the thread identifiers of the threads in the given array.
	*/
	private static long[] threadIds(Thread[] threads) {
	return Stream.of(threads)
	.mapToLong(Thread::threadId)
	.toArray();
	}
	}