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/*
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* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package java.lang.management;
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import java.util.Map;
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/**
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* The management interface for the thread system of
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* the Java virtual machine.
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*
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* <p> A Java virtual machine has a single instance of the implementation
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* class of this interface. This instance implementing this interface is
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* an <a href="ManagementFactory.html#MXBean">MXBean</a>
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* that can be obtained by calling
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* the {@link ManagementFactory#getThreadMXBean} method or
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* from the {@link ManagementFactory#getPlatformMBeanServer
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* platform <tt>MBeanServer</tt>} method.
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*
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* <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for
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* the thread system within an MBeanServer is:
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* <blockquote>
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* {@link ManagementFactory#THREAD_MXBEAN_NAME
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* <tt>java.lang:type=Threading</tt>}
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* </blockquote>
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*
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* <h4>Thread ID</h4>
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* Thread ID is a positive long value returned by calling the
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* {@link java.lang.Thread#getId} method for a thread.
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* The thread ID is unique during its lifetime. When a thread
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* is terminated, this thread ID may be reused.
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*
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* <p> Some methods in this interface take a thread ID or an array
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* of thread IDs as the input parameter and return per-thread information.
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*
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* <h4>Thread CPU time</h4>
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* A Java virtual machine implementation may support measuring
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* the CPU time for the current thread, for any thread, or for no threads.
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*
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* <p>
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* The {@link #isThreadCpuTimeSupported} method can be used to determine
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* if a Java virtual machine supports measuring of the CPU time for any
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* thread. The {@link #isCurrentThreadCpuTimeSupported} method can
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* be used to determine if a Java virtual machine supports measuring of
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* the CPU time for the current thread.
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* A Java virtual machine implementation that supports CPU time measurement
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* for any thread will also support that for the current thread.
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*
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* <p> The CPU time provided by this interface has nanosecond precision
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* but not necessarily nanosecond accuracy.
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*
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* <p>
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* A Java virtual machine may disable CPU time measurement
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* by default.
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* The {@link #isThreadCpuTimeEnabled} and {@link #setThreadCpuTimeEnabled}
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* methods can be used to test if CPU time measurement is enabled
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* and to enable/disable this support respectively.
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* Enabling thread CPU measurement could be expensive in some
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* Java virtual machine implementations.
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*
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* <h4>Thread Contention Monitoring</h4>
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* Some Java virtual machines may support thread contention monitoring.
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* When thread contention monitoring is enabled, the accumulated elapsed
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* time that the thread has blocked for synchronization or waited for
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* notification will be collected and returned in the
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* <a href="ThreadInfo.html#SyncStats"><tt>ThreadInfo</tt></a> object.
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* <p>
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* The {@link #isThreadContentionMonitoringSupported} method can be used to
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* determine if a Java virtual machine supports thread contention monitoring.
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* The thread contention monitoring is disabled by default. The
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* {@link #setThreadContentionMonitoringEnabled} method can be used to enable
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* thread contention monitoring.
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*
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* <h4>Synchronization Information and Deadlock Detection</h4>
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* Some Java virtual machines may support monitoring of
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* {@linkplain #isObjectMonitorUsageSupported object monitor usage} and
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* {@linkplain #isSynchronizerUsageSupported ownable synchronizer usage}.
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* The {@link #getThreadInfo(long[], boolean, boolean)} and
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* {@link #dumpAllThreads} methods can be used to obtain the thread stack trace
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* and synchronization information including which
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* {@linkplain LockInfo <i>lock</i>} a thread is blocked to
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* acquire or waiting on and which locks the thread currently owns.
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* <p>
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* The <tt>ThreadMXBean</tt> interface provides the
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* {@link #findMonitorDeadlockedThreads} and
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* {@link #findDeadlockedThreads} methods to find deadlocks in
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* the running application.
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*
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* @see <a href="../../../javax/management/package-summary.html">
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* JMX Specification.</a>
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* @see <a href="package-summary.html#examples">
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* Ways to Access MXBeans</a>
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*
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* @author Mandy Chung
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* @since 1.5
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*/
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public interface ThreadMXBean {
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/**
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* Returns the current number of live threads including both
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* daemon and non-daemon threads.
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*
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* @return the current number of live threads.
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*/
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public int getThreadCount();
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/**
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* Returns the peak live thread count since the Java virtual machine
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* started or peak was reset.
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*
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* @return the peak live thread count.
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*/
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public int getPeakThreadCount();
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/**
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* Returns the total number of threads created and also started
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* since the Java virtual machine started.
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*
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* @return the total number of threads started.
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*/
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public long getTotalStartedThreadCount();
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/**
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* Returns the current number of live daemon threads.
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*
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* @return the current number of live daemon threads.
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*/
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public int getDaemonThreadCount();
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/**
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* Returns all live thread IDs.
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* Some threads included in the returned array
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* may have been terminated when this method returns.
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*
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* @return an array of <tt>long</tt>, each is a thread ID.
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*
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("monitor").
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*/
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public long[] getAllThreadIds();
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/**
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* Returns the thread info for a thread of the specified
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* <tt>id</tt> with no stack trace.
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* This method is equivalent to calling:
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* <blockquote>
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* {@link #getThreadInfo(long, int) getThreadInfo(id, 0);}
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* </blockquote>
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*
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* <p>
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* This method returns a <tt>ThreadInfo</tt> object representing
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* the thread information for the thread of the specified ID.
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* The stack trace, locked monitors, and locked synchronizers
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* in the returned <tt>ThreadInfo</tt> object will
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* be empty.
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*
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* If a thread of the given ID is not alive or does not exist,
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* this method will return <tt>null</tt>. A thread is alive if
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* it has been started and has not yet died.
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*
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* <p>
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* <b>MBeanServer access</b>:<br>
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* The mapped type of <tt>ThreadInfo</tt> is
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* <tt>CompositeData</tt> with attributes as specified in the
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* {@link ThreadInfo#from ThreadInfo.from} method.
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*
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* @param id the thread ID of the thread. Must be positive.
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*
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* @return a {@link ThreadInfo} object for the thread of the given ID
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* with no stack trace, no locked monitor and no synchronizer info;
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* <tt>null</tt> if the thread of the given ID is not alive or
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* it does not exist.
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*
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* @throws IllegalArgumentException if <tt>id <= 0</tt>.
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("monitor").
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*/
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public ThreadInfo getThreadInfo(long id);
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/**
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* Returns the thread info for each thread
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* whose ID is in the input array <tt>ids</tt> with no stack trace.
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* This method is equivalent to calling:
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* <blockquote><pre>
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* {@link #getThreadInfo(long[], int) getThreadInfo}(ids, 0);
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* </pre></blockquote>
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*
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* <p>
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* This method returns an array of the <tt>ThreadInfo</tt> objects.
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* The stack trace, locked monitors, and locked synchronizers
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* in each <tt>ThreadInfo</tt> object will be empty.
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*
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* If a thread of a given ID is not alive or does not exist,
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* the corresponding element in the returned array will
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* contain <tt>null</tt>. A thread is alive if
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* it has been started and has not yet died.
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*
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* <p>
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* <b>MBeanServer access</b>:<br>
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* The mapped type of <tt>ThreadInfo</tt> is
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* <tt>CompositeData</tt> with attributes as specified in the
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* {@link ThreadInfo#from ThreadInfo.from} method.
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*
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* @param ids an array of thread IDs.
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* @return an array of the {@link ThreadInfo} objects, each containing
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* information about a thread whose ID is in the corresponding
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* element of the input array of IDs
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* with no stack trace, no locked monitor and no synchronizer info.
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*
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* @throws IllegalArgumentException if any element in the input array
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* <tt>ids</tt> is <tt><= 0</tt>.
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("monitor").
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*/
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public ThreadInfo[] getThreadInfo(long[] ids);
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/**
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* Returns a thread info for a thread of the specified <tt>id</tt>,
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* with stack trace of a specified number of stack trace elements.
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* The <tt>maxDepth</tt> parameter indicates the maximum number of
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* {@link StackTraceElement} to be retrieved from the stack trace.
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* If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of
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* the thread will be dumped.
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* If <tt>maxDepth == 0</tt>, no stack trace of the thread
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* will be dumped.
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* This method does not obtain the locked monitors and locked
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* synchronizers of the thread.
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* <p>
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* When the Java virtual machine has no stack trace information
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* about a thread or <tt>maxDepth == 0</tt>,
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* the stack trace in the
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* <tt>ThreadInfo</tt> object will be an empty array of
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* <tt>StackTraceElement</tt>.
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*
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* <p>
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* If a thread of the given ID is not alive or does not exist,
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* this method will return <tt>null</tt>. A thread is alive if
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* it has been started and has not yet died.
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*
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* <p>
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* <b>MBeanServer access</b>:<br>
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* The mapped type of <tt>ThreadInfo</tt> is
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* <tt>CompositeData</tt> with attributes as specified in the
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* {@link ThreadInfo#from ThreadInfo.from} method.
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*
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* @param id the thread ID of the thread. Must be positive.
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* @param maxDepth the maximum number of entries in the stack trace
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* to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request
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* the entire stack to be dumped.
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*
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* @return a {@link ThreadInfo} of the thread of the given ID
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* with no locked monitor and synchronizer info.
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* <tt>null</tt> if the thread of the given ID is not alive or
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* it does not exist.
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*
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* @throws IllegalArgumentException if <tt>id <= 0</tt>.
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* @throws IllegalArgumentException if <tt>maxDepth is negative</tt>.
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("monitor").
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*
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*/
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public ThreadInfo getThreadInfo(long id, int maxDepth);
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/**
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* Returns the thread info for each thread
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* whose ID is in the input array <tt>ids</tt>,
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* with stack trace of a specified number of stack trace elements.
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* The <tt>maxDepth</tt> parameter indicates the maximum number of
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* {@link StackTraceElement} to be retrieved from the stack trace.
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* If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of
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* the thread will be dumped.
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* If <tt>maxDepth == 0</tt>, no stack trace of the thread
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* will be dumped.
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* This method does not obtain the locked monitors and locked
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* synchronizers of the threads.
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* <p>
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* When the Java virtual machine has no stack trace information
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* about a thread or <tt>maxDepth == 0</tt>,
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* the stack trace in the
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* <tt>ThreadInfo</tt> object will be an empty array of
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* <tt>StackTraceElement</tt>.
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* <p>
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* This method returns an array of the <tt>ThreadInfo</tt> objects,
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* each is the thread information about the thread with the same index
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* as in the <tt>ids</tt> array.
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* If a thread of the given ID is not alive or does not exist,
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* <tt>null</tt> will be set in the corresponding element
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* in the returned array. A thread is alive if
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* it has been started and has not yet died.
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*
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* <p>
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* <b>MBeanServer access</b>:<br>
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* The mapped type of <tt>ThreadInfo</tt> is
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* <tt>CompositeData</tt> with attributes as specified in the
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* {@link ThreadInfo#from ThreadInfo.from} method.
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*
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* @param ids an array of thread IDs
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* @param maxDepth the maximum number of entries in the stack trace
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* to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request
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* the entire stack to be dumped.
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*
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* @return an array of the {@link ThreadInfo} objects, each containing
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* information about a thread whose ID is in the corresponding
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* element of the input array of IDs with no locked monitor and
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* synchronizer info.
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*
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* @throws IllegalArgumentException if <tt>maxDepth is negative</tt>.
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* @throws IllegalArgumentException if any element in the input array
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* <tt>ids</tt> is <tt><= 0</tt>.
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("monitor").
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*
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*/
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public ThreadInfo[] getThreadInfo(long[] ids, int maxDepth);
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/**
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* Tests if the Java virtual machine supports thread contention monitoring.
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*
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* @return
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* <tt>true</tt>
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* if the Java virtual machine supports thread contention monitoring;
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* <tt>false</tt> otherwise.
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*/
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public boolean isThreadContentionMonitoringSupported();
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/**
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* Tests if thread contention monitoring is enabled.
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*
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* @return <tt>true</tt> if thread contention monitoring is enabled;
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* <tt>false</tt> otherwise.
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*
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* @throws java.lang.UnsupportedOperationException if the Java virtual
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* machine does not support thread contention monitoring.
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*
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* @see #isThreadContentionMonitoringSupported
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*/
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public boolean isThreadContentionMonitoringEnabled();
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/**
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* Enables or disables thread contention monitoring.
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* Thread contention monitoring is disabled by default.
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*
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* @param enable <tt>true</tt> to enable;
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* <tt>false</tt> to disable.
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*
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* @throws java.lang.UnsupportedOperationException if the Java
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* virtual machine does not support thread contention monitoring.
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*
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* @throws java.lang.SecurityException if a security manager
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* exists and the caller does not have
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* ManagementPermission("control").
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*
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* @see #isThreadContentionMonitoringSupported
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*/
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public void setThreadContentionMonitoringEnabled(boolean enable);
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/**
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* Returns the total CPU time for the current thread in nanoseconds.
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* The returned value is of nanoseconds precision but
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* not necessarily nanoseconds accuracy.
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* If the implementation distinguishes between user mode time and system
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* mode time, the returned CPU time is the amount of time that
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|
390 |
* the current thread has executed in user mode or system mode.
|
|
391 |
*
|
|
392 |
* <p>
|
|
393 |
* This is a convenient method for local management use and is
|
|
394 |
* equivalent to calling:
|
|
395 |
* <blockquote><pre>
|
|
396 |
* {@link #getThreadCpuTime getThreadCpuTime}(Thread.currentThread().getId());
|
|
397 |
* </pre></blockquote>
|
|
398 |
*
|
|
399 |
* @return the total CPU time for the current thread if CPU time
|
|
400 |
* measurement is enabled; <tt>-1</tt> otherwise.
|
|
401 |
*
|
|
402 |
* @throws java.lang.UnsupportedOperationException if the Java
|
|
403 |
* virtual machine does not support CPU time measurement for
|
|
404 |
* the current thread.
|
|
405 |
*
|
|
406 |
* @see #getCurrentThreadUserTime
|
|
407 |
* @see #isCurrentThreadCpuTimeSupported
|
|
408 |
* @see #isThreadCpuTimeEnabled
|
|
409 |
* @see #setThreadCpuTimeEnabled
|
|
410 |
*/
|
|
411 |
public long getCurrentThreadCpuTime();
|
|
412 |
|
|
413 |
/**
|
|
414 |
* Returns the CPU time that the current thread has executed
|
|
415 |
* in user mode in nanoseconds.
|
|
416 |
* The returned value is of nanoseconds precision but
|
|
417 |
* not necessarily nanoseconds accuracy.
|
|
418 |
*
|
|
419 |
* <p>
|
|
420 |
* This is a convenient method for local management use and is
|
|
421 |
* equivalent to calling:
|
|
422 |
* <blockquote><pre>
|
|
423 |
* {@link #getThreadUserTime getThreadUserTime}(Thread.currentThread().getId());
|
|
424 |
* </pre></blockquote>
|
|
425 |
*
|
|
426 |
* @return the user-level CPU time for the current thread if CPU time
|
|
427 |
* measurement is enabled; <tt>-1</tt> otherwise.
|
|
428 |
*
|
|
429 |
* @throws java.lang.UnsupportedOperationException if the Java
|
|
430 |
* virtual machine does not support CPU time measurement for
|
|
431 |
* the current thread.
|
|
432 |
*
|
|
433 |
* @see #getCurrentThreadCpuTime
|
|
434 |
* @see #isCurrentThreadCpuTimeSupported
|
|
435 |
* @see #isThreadCpuTimeEnabled
|
|
436 |
* @see #setThreadCpuTimeEnabled
|
|
437 |
*/
|
|
438 |
public long getCurrentThreadUserTime();
|
|
439 |
|
|
440 |
/**
|
|
441 |
* Returns the total CPU time for a thread of the specified ID in nanoseconds.
|
|
442 |
* The returned value is of nanoseconds precision but
|
|
443 |
* not necessarily nanoseconds accuracy.
|
|
444 |
* If the implementation distinguishes between user mode time and system
|
|
445 |
* mode time, the returned CPU time is the amount of time that
|
|
446 |
* the thread has executed in user mode or system mode.
|
|
447 |
*
|
|
448 |
* <p>
|
|
449 |
* If the thread of the specified ID is not alive or does not exist,
|
|
450 |
* this method returns <tt>-1</tt>. If CPU time measurement
|
|
451 |
* is disabled, this method returns <tt>-1</tt>.
|
|
452 |
* A thread is alive if it has been started and has not yet died.
|
|
453 |
* <p>
|
|
454 |
* If CPU time measurement is enabled after the thread has started,
|
|
455 |
* the Java virtual machine implementation may choose any time up to
|
|
456 |
* and including the time that the capability is enabled as the point
|
|
457 |
* where CPU time measurement starts.
|
|
458 |
*
|
|
459 |
* @param id the thread ID of a thread
|
|
460 |
* @return the total CPU time for a thread of the specified ID
|
|
461 |
* if the thread of the specified ID exists, the thread is alive,
|
|
462 |
* and CPU time measurement is enabled;
|
|
463 |
* <tt>-1</tt> otherwise.
|
|
464 |
*
|
|
465 |
* @throws IllegalArgumentException if <tt>id <= 0 </tt>.
|
|
466 |
* @throws java.lang.UnsupportedOperationException if the Java
|
|
467 |
* virtual machine does not support CPU time measurement for
|
|
468 |
* other threads.
|
|
469 |
*
|
|
470 |
* @see #getThreadUserTime
|
|
471 |
* @see #isThreadCpuTimeSupported
|
|
472 |
* @see #isThreadCpuTimeEnabled
|
|
473 |
* @see #setThreadCpuTimeEnabled
|
|
474 |
*/
|
|
475 |
public long getThreadCpuTime(long id);
|
|
476 |
|
|
477 |
/**
|
|
478 |
* Returns the CPU time that a thread of the specified ID
|
|
479 |
* has executed in user mode in nanoseconds.
|
|
480 |
* The returned value is of nanoseconds precision but
|
|
481 |
* not necessarily nanoseconds accuracy.
|
|
482 |
*
|
|
483 |
* <p>
|
|
484 |
* If the thread of the specified ID is not alive or does not exist,
|
|
485 |
* this method returns <tt>-1</tt>. If CPU time measurement
|
|
486 |
* is disabled, this method returns <tt>-1</tt>.
|
|
487 |
* A thread is alive if it has been started and has not yet died.
|
|
488 |
* <p>
|
|
489 |
* If CPU time measurement is enabled after the thread has started,
|
|
490 |
* the Java virtual machine implementation may choose any time up to
|
|
491 |
* and including the time that the capability is enabled as the point
|
|
492 |
* where CPU time measurement starts.
|
|
493 |
*
|
|
494 |
* @param id the thread ID of a thread
|
|
495 |
* @return the user-level CPU time for a thread of the specified ID
|
|
496 |
* if the thread of the specified ID exists, the thread is alive,
|
|
497 |
* and CPU time measurement is enabled;
|
|
498 |
* <tt>-1</tt> otherwise.
|
|
499 |
*
|
|
500 |
* @throws IllegalArgumentException if <tt>id <= 0 </tt>.
|
|
501 |
* @throws java.lang.UnsupportedOperationException if the Java
|
|
502 |
* virtual machine does not support CPU time measurement for
|
|
503 |
* other threads.
|
|
504 |
*
|
|
505 |
* @see #getThreadCpuTime
|
|
506 |
* @see #isThreadCpuTimeSupported
|
|
507 |
* @see #isThreadCpuTimeEnabled
|
|
508 |
* @see #setThreadCpuTimeEnabled
|
|
509 |
*/
|
|
510 |
public long getThreadUserTime(long id);
|
|
511 |
|
|
512 |
/**
|
|
513 |
* Tests if the Java virtual machine implementation supports CPU time
|
|
514 |
* measurement for any thread.
|
|
515 |
* A Java virtual machine implementation that supports CPU time
|
|
516 |
* measurement for any thread will also support CPU time
|
|
517 |
* measurement for the current thread.
|
|
518 |
*
|
|
519 |
* @return
|
|
520 |
* <tt>true</tt>
|
|
521 |
* if the Java virtual machine supports CPU time
|
|
522 |
* measurement for any thread;
|
|
523 |
* <tt>false</tt> otherwise.
|
|
524 |
*/
|
|
525 |
public boolean isThreadCpuTimeSupported();
|
|
526 |
|
|
527 |
/**
|
|
528 |
* Tests if the Java virtual machine supports CPU time
|
|
529 |
* measurement for the current thread.
|
|
530 |
* This method returns <tt>true</tt> if {@link #isThreadCpuTimeSupported}
|
|
531 |
* returns <tt>true</tt>.
|
|
532 |
*
|
|
533 |
* @return
|
|
534 |
* <tt>true</tt>
|
|
535 |
* if the Java virtual machine supports CPU time
|
|
536 |
* measurement for current thread;
|
|
537 |
* <tt>false</tt> otherwise.
|
|
538 |
*/
|
|
539 |
public boolean isCurrentThreadCpuTimeSupported();
|
|
540 |
|
|
541 |
/**
|
|
542 |
* Tests if thread CPU time measurement is enabled.
|
|
543 |
*
|
|
544 |
* @return <tt>true</tt> if thread CPU time measurement is enabled;
|
|
545 |
* <tt>false</tt> otherwise.
|
|
546 |
*
|
|
547 |
* @throws java.lang.UnsupportedOperationException if the Java virtual
|
|
548 |
* machine does not support CPU time measurement for other threads
|
|
549 |
* nor for the current thread.
|
|
550 |
*
|
|
551 |
* @see #isThreadCpuTimeSupported
|
|
552 |
* @see #isCurrentThreadCpuTimeSupported
|
|
553 |
*/
|
|
554 |
public boolean isThreadCpuTimeEnabled();
|
|
555 |
|
|
556 |
/**
|
|
557 |
* Enables or disables thread CPU time measurement. The default
|
|
558 |
* is platform dependent.
|
|
559 |
*
|
|
560 |
* @param enable <tt>true</tt> to enable;
|
|
561 |
* <tt>false</tt> to disable.
|
|
562 |
*
|
|
563 |
* @throws java.lang.UnsupportedOperationException if the Java
|
|
564 |
* virtual machine does not support CPU time measurement for
|
|
565 |
* any threads nor for the current thread.
|
|
566 |
*
|
|
567 |
* @throws java.lang.SecurityException if a security manager
|
|
568 |
* exists and the caller does not have
|
|
569 |
* ManagementPermission("control").
|
|
570 |
*
|
|
571 |
* @see #isThreadCpuTimeSupported
|
|
572 |
* @see #isCurrentThreadCpuTimeSupported
|
|
573 |
*/
|
|
574 |
public void setThreadCpuTimeEnabled(boolean enable);
|
|
575 |
|
|
576 |
/**
|
|
577 |
* Finds cycles of threads that are in deadlock waiting to acquire
|
|
578 |
* object monitors. That is, threads that are blocked waiting to enter a
|
|
579 |
* synchronization block or waiting to reenter a synchronization block
|
|
580 |
* after an {@link Object#wait Object.wait} call,
|
|
581 |
* where each thread owns one monitor while
|
|
582 |
* trying to obtain another monitor already held by another thread
|
|
583 |
* in a cycle.
|
|
584 |
* <p>
|
|
585 |
* More formally, a thread is <em>monitor deadlocked</em> if it is
|
|
586 |
* part of a cycle in the relation "is waiting for an object monitor
|
|
587 |
* owned by". In the simplest case, thread A is blocked waiting
|
|
588 |
* for a monitor owned by thread B, and thread B is blocked waiting
|
|
589 |
* for a monitor owned by thread A.
|
|
590 |
* <p>
|
|
591 |
* This method is designed for troubleshooting use, but not for
|
|
592 |
* synchronization control. It might be an expensive operation.
|
|
593 |
* <p>
|
|
594 |
* This method finds deadlocks involving only object monitors.
|
|
595 |
* To find deadlocks involving both object monitors and
|
|
596 |
* <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>,
|
|
597 |
* the {@link #findDeadlockedThreads findDeadlockedThreads} method
|
|
598 |
* should be used.
|
|
599 |
*
|
|
600 |
* @return an array of IDs of the threads that are monitor
|
|
601 |
* deadlocked, if any; <tt>null</tt> otherwise.
|
|
602 |
*
|
|
603 |
* @throws java.lang.SecurityException if a security manager
|
|
604 |
* exists and the caller does not have
|
|
605 |
* ManagementPermission("monitor").
|
|
606 |
*
|
|
607 |
* @see #findDeadlockedThreads
|
|
608 |
*/
|
|
609 |
public long[] findMonitorDeadlockedThreads();
|
|
610 |
|
|
611 |
/**
|
|
612 |
* Resets the peak thread count to the current number of
|
|
613 |
* live threads.
|
|
614 |
*
|
|
615 |
* @throws java.lang.SecurityException if a security manager
|
|
616 |
* exists and the caller does not have
|
|
617 |
* ManagementPermission("control").
|
|
618 |
*
|
|
619 |
* @see #getPeakThreadCount
|
|
620 |
* @see #getThreadCount
|
|
621 |
*/
|
|
622 |
public void resetPeakThreadCount();
|
|
623 |
|
|
624 |
/**
|
|
625 |
* Finds cycles of threads that are in deadlock waiting to acquire
|
|
626 |
* object monitors or
|
|
627 |
* <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>.
|
|
628 |
*
|
|
629 |
* Threads are <em>deadlocked</em> in a cycle waiting for a lock of
|
|
630 |
* these two types if each thread owns one lock while
|
|
631 |
* trying to acquire another lock already held
|
|
632 |
* by another thread in the cycle.
|
|
633 |
* <p>
|
|
634 |
* This method is designed for troubleshooting use, but not for
|
|
635 |
* synchronization control. It might be an expensive operation.
|
|
636 |
*
|
|
637 |
* @return an array of IDs of the threads that are
|
|
638 |
* deadlocked waiting for object monitors or ownable synchronizers, if any;
|
|
639 |
* <tt>null</tt> otherwise.
|
|
640 |
*
|
|
641 |
* @throws java.lang.SecurityException if a security manager
|
|
642 |
* exists and the caller does not have
|
|
643 |
* ManagementPermission("monitor").
|
|
644 |
* @throws java.lang.UnsupportedOperationException if the Java virtual
|
|
645 |
* machine does not support monitoriing of ownable synchronizer usage.
|
|
646 |
*
|
|
647 |
* @see #isSynchronizerUsageSupported
|
|
648 |
* @see #findMonitorDeadlockedThreads
|
|
649 |
* @since 1.6
|
|
650 |
*/
|
|
651 |
public long[] findDeadlockedThreads();
|
|
652 |
|
|
653 |
/**
|
|
654 |
* Tests if the Java virtual machine supports monitoring of
|
|
655 |
* object monitor usage.
|
|
656 |
*
|
|
657 |
* @return
|
|
658 |
* <tt>true</tt>
|
|
659 |
* if the Java virtual machine supports monitoring of
|
|
660 |
* object monitor usage;
|
|
661 |
* <tt>false</tt> otherwise.
|
|
662 |
*
|
|
663 |
* @see #dumpAllThreads
|
|
664 |
* @since 1.6
|
|
665 |
*/
|
|
666 |
public boolean isObjectMonitorUsageSupported();
|
|
667 |
|
|
668 |
/**
|
|
669 |
* Tests if the Java virtual machine supports monitoring of
|
|
670 |
* <a href="LockInfo.html#OwnableSynchronizer">
|
|
671 |
* ownable synchronizer</a> usage.
|
|
672 |
*
|
|
673 |
* @return
|
|
674 |
* <tt>true</tt>
|
|
675 |
* if the Java virtual machine supports monitoring of ownable
|
|
676 |
* synchronizer usage;
|
|
677 |
* <tt>false</tt> otherwise.
|
|
678 |
*
|
|
679 |
* @see #dumpAllThreads
|
|
680 |
* @since 1.6
|
|
681 |
*/
|
|
682 |
public boolean isSynchronizerUsageSupported();
|
|
683 |
|
|
684 |
/**
|
|
685 |
* Returns the thread info for each thread
|
|
686 |
* whose ID is in the input array <tt>ids</tt>, with stack trace
|
|
687 |
* and synchronization information.
|
|
688 |
*
|
|
689 |
* <p>
|
|
690 |
* This method obtains a snapshot of the thread information
|
|
691 |
* for each thread including:
|
|
692 |
* <ul>
|
|
693 |
* <li>the entire stack trace,</li>
|
|
694 |
* <li>the object monitors currently locked by the thread
|
|
695 |
* if <tt>lockedMonitors</tt> is <tt>true</tt>, and</li>
|
|
696 |
* <li>the <a href="LockInfo.html#OwnableSynchronizer">
|
|
697 |
* ownable synchronizers</a> currently locked by the thread
|
|
698 |
* if <tt>lockedSynchronizers</tt> is <tt>true</tt>.</li>
|
|
699 |
* </ul>
|
|
700 |
* <p>
|
|
701 |
* This method returns an array of the <tt>ThreadInfo</tt> objects,
|
|
702 |
* each is the thread information about the thread with the same index
|
|
703 |
* as in the <tt>ids</tt> array.
|
|
704 |
* If a thread of the given ID is not alive or does not exist,
|
|
705 |
* <tt>null</tt> will be set in the corresponding element
|
|
706 |
* in the returned array. A thread is alive if
|
|
707 |
* it has been started and has not yet died.
|
|
708 |
* <p>
|
|
709 |
* If a thread does not lock any object monitor or <tt>lockedMonitors</tt>
|
|
710 |
* is <tt>false</tt>, the returned <tt>ThreadInfo</tt> object will have an
|
|
711 |
* empty <tt>MonitorInfo</tt> array. Similarly, if a thread does not
|
|
712 |
* lock any synchronizer or <tt>lockedSynchronizers</tt> is <tt>false</tt>,
|
|
713 |
* the returned <tt>ThreadInfo</tt> object
|
|
714 |
* will have an empty <tt>LockInfo</tt> array.
|
|
715 |
*
|
|
716 |
* <p>
|
|
717 |
* When both <tt>lockedMonitors</tt> and <tt>lockedSynchronizers</tt>
|
|
718 |
* parameters are <tt>false</tt>, it is equivalent to calling:
|
|
719 |
* <blockquote><pre>
|
|
720 |
* {@link #getThreadInfo(long[], int) getThreadInfo(ids, Integer.MAX_VALUE)}
|
|
721 |
* </pre></blockquote>
|
|
722 |
*
|
|
723 |
* <p>
|
|
724 |
* This method is designed for troubleshooting use, but not for
|
|
725 |
* synchronization control. It might be an expensive operation.
|
|
726 |
*
|
|
727 |
* <p>
|
|
728 |
* <b>MBeanServer access</b>:<br>
|
|
729 |
* The mapped type of <tt>ThreadInfo</tt> is
|
|
730 |
* <tt>CompositeData</tt> with attributes as specified in the
|
|
731 |
* {@link ThreadInfo#from ThreadInfo.from} method.
|
|
732 |
*
|
|
733 |
* @param ids an array of thread IDs.
|
|
734 |
* @param lockedMonitors if <tt>true</tt>, retrieves all locked monitors.
|
|
735 |
* @param lockedSynchronizers if <tt>true</tt>, retrieves all locked
|
|
736 |
* ownable synchronizers.
|
|
737 |
*
|
|
738 |
* @return an array of the {@link ThreadInfo} objects, each containing
|
|
739 |
* information about a thread whose ID is in the corresponding
|
|
740 |
* element of the input array of IDs.
|
|
741 |
*
|
|
742 |
* @throws java.lang.SecurityException if a security manager
|
|
743 |
* exists and the caller does not have
|
|
744 |
* ManagementPermission("monitor").
|
|
745 |
* @throws java.lang.UnsupportedOperationException
|
|
746 |
* <ul>
|
|
747 |
* <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but
|
|
748 |
* the Java virtual machine does not support monitoring
|
|
749 |
* of {@linkplain #isObjectMonitorUsageSupported
|
|
750 |
* object monitor usage}; or</li>
|
|
751 |
* <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but
|
|
752 |
* the Java virtual machine does not support monitoring
|
|
753 |
* of {@linkplain #isSynchronizerUsageSupported
|
|
754 |
* ownable synchronizer usage}.</li>
|
|
755 |
* </ul>
|
|
756 |
*
|
|
757 |
* @see #isObjectMonitorUsageSupported
|
|
758 |
* @see #isSynchronizerUsageSupported
|
|
759 |
*
|
|
760 |
* @since 1.6
|
|
761 |
*/
|
|
762 |
public ThreadInfo[] getThreadInfo(long[] ids, boolean lockedMonitors, boolean lockedSynchronizers);
|
|
763 |
|
|
764 |
/**
|
|
765 |
* Returns the thread info for all live threads with stack trace
|
|
766 |
* and synchronization information.
|
|
767 |
* Some threads included in the returned array
|
|
768 |
* may have been terminated when this method returns.
|
|
769 |
*
|
|
770 |
* <p>
|
|
771 |
* This method returns an array of {@link ThreadInfo} objects
|
|
772 |
* as specified in the {@link #getThreadInfo(long[], boolean, boolean)}
|
|
773 |
* method.
|
|
774 |
*
|
|
775 |
* @param lockedMonitors if <tt>true</tt>, dump all locked monitors.
|
|
776 |
* @param lockedSynchronizers if <tt>true</tt>, dump all locked
|
|
777 |
* ownable synchronizers.
|
|
778 |
*
|
|
779 |
* @return an array of {@link ThreadInfo} for all live threads.
|
|
780 |
*
|
|
781 |
* @throws java.lang.SecurityException if a security manager
|
|
782 |
* exists and the caller does not have
|
|
783 |
* ManagementPermission("monitor").
|
|
784 |
* @throws java.lang.UnsupportedOperationException
|
|
785 |
* <ul>
|
|
786 |
* <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but
|
|
787 |
* the Java virtual machine does not support monitoring
|
|
788 |
* of {@linkplain #isObjectMonitorUsageSupported
|
|
789 |
* object monitor usage}; or</li>
|
|
790 |
* <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but
|
|
791 |
* the Java virtual machine does not support monitoring
|
|
792 |
* of {@linkplain #isSynchronizerUsageSupported
|
|
793 |
* ownable synchronizer usage}.</li>
|
|
794 |
* </ul>
|
|
795 |
*
|
|
796 |
* @see #isObjectMonitorUsageSupported
|
|
797 |
* @see #isSynchronizerUsageSupported
|
|
798 |
*
|
|
799 |
* @since 1.6
|
|
800 |
*/
|
|
801 |
public ThreadInfo[] dumpAllThreads(boolean lockedMonitors, boolean lockedSynchronizers);
|
|
802 |
}
|