--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/lang/management/ThreadMXBean.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,802 @@
+/*
+ * Copyright 2003-2006 Sun Microsystems, Inc. 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. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.lang.management;
+
+import java.util.Map;
+
+/**
+ * The management interface for the thread system of
+ * the Java virtual machine.
+ *
+ * <p> A Java virtual machine has a single instance of the implementation
+ * class of this interface. This instance implementing this interface is
+ * an <a href="ManagementFactory.html#MXBean">MXBean</a>
+ * that can be obtained by calling
+ * the {@link ManagementFactory#getThreadMXBean} method or
+ * from the {@link ManagementFactory#getPlatformMBeanServer
+ * platform <tt>MBeanServer</tt>} method.
+ *
+ * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for
+ * the thread system within an MBeanServer is:
+ * <blockquote>
+ * {@link ManagementFactory#THREAD_MXBEAN_NAME
+ * <tt>java.lang:type=Threading</tt>}
+ * </blockquote>
+ *
+ * <h4>Thread ID</h4>
+ * Thread ID is a positive long value returned by calling the
+ * {@link java.lang.Thread#getId} method for a thread.
+ * The thread ID is unique during its lifetime. When a thread
+ * is terminated, this thread ID may be reused.
+ *
+ * <p> Some methods in this interface take a thread ID or an array
+ * of thread IDs as the input parameter and return per-thread information.
+ *
+ * <h4>Thread CPU time</h4>
+ * A Java virtual machine implementation may support measuring
+ * the CPU time for the current thread, for any thread, or for no threads.
+ *
+ * <p>
+ * The {@link #isThreadCpuTimeSupported} method can be used to determine
+ * if a Java virtual machine supports measuring of the CPU time for any
+ * thread. The {@link #isCurrentThreadCpuTimeSupported} method can
+ * be used to determine if a Java virtual machine supports measuring of
+ * the CPU time for the current thread.
+ * A Java virtual machine implementation that supports CPU time measurement
+ * for any thread will also support that for the current thread.
+ *
+ * <p> The CPU time provided by this interface has nanosecond precision
+ * but not necessarily nanosecond accuracy.
+ *
+ * <p>
+ * A Java virtual machine may disable CPU time measurement
+ * by default.
+ * The {@link #isThreadCpuTimeEnabled} and {@link #setThreadCpuTimeEnabled}
+ * methods can be used to test if CPU time measurement is enabled
+ * and to enable/disable this support respectively.
+ * Enabling thread CPU measurement could be expensive in some
+ * Java virtual machine implementations.
+ *
+ * <h4>Thread Contention Monitoring</h4>
+ * Some Java virtual machines may support thread contention monitoring.
+ * When thread contention monitoring is enabled, the accumulated elapsed
+ * time that the thread has blocked for synchronization or waited for
+ * notification will be collected and returned in the
+ * <a href="ThreadInfo.html#SyncStats"><tt>ThreadInfo</tt></a> object.
+ * <p>
+ * The {@link #isThreadContentionMonitoringSupported} method can be used to
+ * determine if a Java virtual machine supports thread contention monitoring.
+ * The thread contention monitoring is disabled by default. The
+ * {@link #setThreadContentionMonitoringEnabled} method can be used to enable
+ * thread contention monitoring.
+ *
+ * <h4>Synchronization Information and Deadlock Detection</h4>
+ * Some Java virtual machines may support monitoring of
+ * {@linkplain #isObjectMonitorUsageSupported object monitor usage} and
+ * {@linkplain #isSynchronizerUsageSupported ownable synchronizer usage}.
+ * The {@link #getThreadInfo(long[], boolean, boolean)} and
+ * {@link #dumpAllThreads} methods can be used to obtain the thread stack trace
+ * and synchronization information including which
+ * {@linkplain LockInfo <i>lock</i>} a thread is blocked to
+ * acquire or waiting on and which locks the thread currently owns.
+ * <p>
+ * The <tt>ThreadMXBean</tt> interface provides the
+ * {@link #findMonitorDeadlockedThreads} and
+ * {@link #findDeadlockedThreads} methods to find deadlocks in
+ * the running application.
+ *
+ * @see <a href="../../../javax/management/package-summary.html">
+ * JMX Specification.</a>
+ * @see <a href="package-summary.html#examples">
+ * Ways to Access MXBeans</a>
+ *
+ * @author Mandy Chung
+ * @since 1.5
+ */
+
+public interface ThreadMXBean {
+ /**
+ * Returns the current number of live threads including both
+ * daemon and non-daemon threads.
+ *
+ * @return the current number of live threads.
+ */
+ public int getThreadCount();
+
+ /**
+ * Returns the peak live thread count since the Java virtual machine
+ * started or peak was reset.
+ *
+ * @return the peak live thread count.
+ */
+ public int getPeakThreadCount();
+
+ /**
+ * Returns the total number of threads created and also started
+ * since the Java virtual machine started.
+ *
+ * @return the total number of threads started.
+ */
+ public long getTotalStartedThreadCount();
+
+ /**
+ * Returns the current number of live daemon threads.
+ *
+ * @return the current number of live daemon threads.
+ */
+ public int getDaemonThreadCount();
+
+ /**
+ * Returns all live thread IDs.
+ * Some threads included in the returned array
+ * may have been terminated when this method returns.
+ *
+ * @return an array of <tt>long</tt>, each is a thread ID.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ */
+ public long[] getAllThreadIds();
+
+ /**
+ * Returns the thread info for a thread of the specified
+ * <tt>id</tt> with no stack trace.
+ * This method is equivalent to calling:
+ * <blockquote>
+ * {@link #getThreadInfo(long, int) getThreadInfo(id, 0);}
+ * </blockquote>
+ *
+ * <p>
+ * This method returns a <tt>ThreadInfo</tt> object representing
+ * the thread information for the thread of the specified ID.
+ * The stack trace, locked monitors, and locked synchronizers
+ * in the returned <tt>ThreadInfo</tt> object will
+ * be empty.
+ *
+ * If a thread of the given ID is not alive or does not exist,
+ * this method will return <tt>null</tt>. A thread is alive if
+ * it has been started and has not yet died.
+ *
+ * <p>
+ * <b>MBeanServer access</b>:<br>
+ * The mapped type of <tt>ThreadInfo</tt> is
+ * <tt>CompositeData</tt> with attributes as specified in the
+ * {@link ThreadInfo#from ThreadInfo.from} method.
+ *
+ * @param id the thread ID of the thread. Must be positive.
+ *
+ * @return a {@link ThreadInfo} object for the thread of the given ID
+ * with no stack trace, no locked monitor and no synchronizer info;
+ * <tt>null</tt> if the thread of the given ID is not alive or
+ * it does not exist.
+ *
+ * @throws IllegalArgumentException if <tt>id <= 0</tt>.
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ */
+ public ThreadInfo getThreadInfo(long id);
+
+ /**
+ * Returns the thread info for each thread
+ * whose ID is in the input array <tt>ids</tt> with no stack trace.
+ * This method is equivalent to calling:
+ * <blockquote><pre>
+ * {@link #getThreadInfo(long[], int) getThreadInfo}(ids, 0);
+ * </pre></blockquote>
+ *
+ * <p>
+ * This method returns an array of the <tt>ThreadInfo</tt> objects.
+ * The stack trace, locked monitors, and locked synchronizers
+ * in each <tt>ThreadInfo</tt> object will be empty.
+ *
+ * If a thread of a given ID is not alive or does not exist,
+ * the corresponding element in the returned array will
+ * contain <tt>null</tt>. A thread is alive if
+ * it has been started and has not yet died.
+ *
+ * <p>
+ * <b>MBeanServer access</b>:<br>
+ * The mapped type of <tt>ThreadInfo</tt> is
+ * <tt>CompositeData</tt> with attributes as specified in the
+ * {@link ThreadInfo#from ThreadInfo.from} method.
+ *
+ * @param ids an array of thread IDs.
+ * @return an array of the {@link ThreadInfo} objects, each containing
+ * information about a thread whose ID is in the corresponding
+ * element of the input array of IDs
+ * with no stack trace, no locked monitor and no synchronizer info.
+ *
+ * @throws IllegalArgumentException if any element in the input array
+ * <tt>ids</tt> is <tt><= 0</tt>.
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ */
+ public ThreadInfo[] getThreadInfo(long[] ids);
+
+ /**
+ * Returns a thread info for a thread of the specified <tt>id</tt>,
+ * with stack trace of a specified number of stack trace elements.
+ * The <tt>maxDepth</tt> parameter indicates the maximum number of
+ * {@link StackTraceElement} to be retrieved from the stack trace.
+ * If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of
+ * the thread will be dumped.
+ * If <tt>maxDepth == 0</tt>, no stack trace of the thread
+ * will be dumped.
+ * This method does not obtain the locked monitors and locked
+ * synchronizers of the thread.
+ * <p>
+ * When the Java virtual machine has no stack trace information
+ * about a thread or <tt>maxDepth == 0</tt>,
+ * the stack trace in the
+ * <tt>ThreadInfo</tt> object will be an empty array of
+ * <tt>StackTraceElement</tt>.
+ *
+ * <p>
+ * If a thread of the given ID is not alive or does not exist,
+ * this method will return <tt>null</tt>. A thread is alive if
+ * it has been started and has not yet died.
+ *
+ * <p>
+ * <b>MBeanServer access</b>:<br>
+ * The mapped type of <tt>ThreadInfo</tt> is
+ * <tt>CompositeData</tt> with attributes as specified in the
+ * {@link ThreadInfo#from ThreadInfo.from} method.
+ *
+ * @param id the thread ID of the thread. Must be positive.
+ * @param maxDepth the maximum number of entries in the stack trace
+ * to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request
+ * the entire stack to be dumped.
+ *
+ * @return a {@link ThreadInfo} of the thread of the given ID
+ * with no locked monitor and synchronizer info.
+ * <tt>null</tt> if the thread of the given ID is not alive or
+ * it does not exist.
+ *
+ * @throws IllegalArgumentException if <tt>id <= 0</tt>.
+ * @throws IllegalArgumentException if <tt>maxDepth is negative</tt>.
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ *
+ */
+ public ThreadInfo getThreadInfo(long id, int maxDepth);
+
+ /**
+ * Returns the thread info for each thread
+ * whose ID is in the input array <tt>ids</tt>,
+ * with stack trace of a specified number of stack trace elements.
+ * The <tt>maxDepth</tt> parameter indicates the maximum number of
+ * {@link StackTraceElement} to be retrieved from the stack trace.
+ * If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of
+ * the thread will be dumped.
+ * If <tt>maxDepth == 0</tt>, no stack trace of the thread
+ * will be dumped.
+ * This method does not obtain the locked monitors and locked
+ * synchronizers of the threads.
+ * <p>
+ * When the Java virtual machine has no stack trace information
+ * about a thread or <tt>maxDepth == 0</tt>,
+ * the stack trace in the
+ * <tt>ThreadInfo</tt> object will be an empty array of
+ * <tt>StackTraceElement</tt>.
+ * <p>
+ * This method returns an array of the <tt>ThreadInfo</tt> objects,
+ * each is the thread information about the thread with the same index
+ * as in the <tt>ids</tt> array.
+ * If a thread of the given ID is not alive or does not exist,
+ * <tt>null</tt> will be set in the corresponding element
+ * in the returned array. A thread is alive if
+ * it has been started and has not yet died.
+ *
+ * <p>
+ * <b>MBeanServer access</b>:<br>
+ * The mapped type of <tt>ThreadInfo</tt> is
+ * <tt>CompositeData</tt> with attributes as specified in the
+ * {@link ThreadInfo#from ThreadInfo.from} method.
+ *
+ * @param ids an array of thread IDs
+ * @param maxDepth the maximum number of entries in the stack trace
+ * to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request
+ * the entire stack to be dumped.
+ *
+ * @return an array of the {@link ThreadInfo} objects, each containing
+ * information about a thread whose ID is in the corresponding
+ * element of the input array of IDs with no locked monitor and
+ * synchronizer info.
+ *
+ * @throws IllegalArgumentException if <tt>maxDepth is negative</tt>.
+ * @throws IllegalArgumentException if any element in the input array
+ * <tt>ids</tt> is <tt><= 0</tt>.
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ *
+ */
+ public ThreadInfo[] getThreadInfo(long[] ids, int maxDepth);
+
+ /**
+ * Tests if the Java virtual machine supports thread contention monitoring.
+ *
+ * @return
+ * <tt>true</tt>
+ * if the Java virtual machine supports thread contention monitoring;
+ * <tt>false</tt> otherwise.
+ */
+ public boolean isThreadContentionMonitoringSupported();
+
+ /**
+ * Tests if thread contention monitoring is enabled.
+ *
+ * @return <tt>true</tt> if thread contention monitoring is enabled;
+ * <tt>false</tt> otherwise.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java virtual
+ * machine does not support thread contention monitoring.
+ *
+ * @see #isThreadContentionMonitoringSupported
+ */
+ public boolean isThreadContentionMonitoringEnabled();
+
+ /**
+ * Enables or disables thread contention monitoring.
+ * Thread contention monitoring is disabled by default.
+ *
+ * @param enable <tt>true</tt> to enable;
+ * <tt>false</tt> to disable.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support thread contention monitoring.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("control").
+ *
+ * @see #isThreadContentionMonitoringSupported
+ */
+ public void setThreadContentionMonitoringEnabled(boolean enable);
+
+ /**
+ * Returns the total CPU time for the current thread in nanoseconds.
+ * The returned value is of nanoseconds precision but
+ * not necessarily nanoseconds accuracy.
+ * If the implementation distinguishes between user mode time and system
+ * mode time, the returned CPU time is the amount of time that
+ * the current thread has executed in user mode or system mode.
+ *
+ * <p>
+ * This is a convenient method for local management use and is
+ * equivalent to calling:
+ * <blockquote><pre>
+ * {@link #getThreadCpuTime getThreadCpuTime}(Thread.currentThread().getId());
+ * </pre></blockquote>
+ *
+ * @return the total CPU time for the current thread if CPU time
+ * measurement is enabled; <tt>-1</tt> otherwise.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support CPU time measurement for
+ * the current thread.
+ *
+ * @see #getCurrentThreadUserTime
+ * @see #isCurrentThreadCpuTimeSupported
+ * @see #isThreadCpuTimeEnabled
+ * @see #setThreadCpuTimeEnabled
+ */
+ public long getCurrentThreadCpuTime();
+
+ /**
+ * Returns the CPU time that the current thread has executed
+ * in user mode in nanoseconds.
+ * The returned value is of nanoseconds precision but
+ * not necessarily nanoseconds accuracy.
+ *
+ * <p>
+ * This is a convenient method for local management use and is
+ * equivalent to calling:
+ * <blockquote><pre>
+ * {@link #getThreadUserTime getThreadUserTime}(Thread.currentThread().getId());
+ * </pre></blockquote>
+ *
+ * @return the user-level CPU time for the current thread if CPU time
+ * measurement is enabled; <tt>-1</tt> otherwise.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support CPU time measurement for
+ * the current thread.
+ *
+ * @see #getCurrentThreadCpuTime
+ * @see #isCurrentThreadCpuTimeSupported
+ * @see #isThreadCpuTimeEnabled
+ * @see #setThreadCpuTimeEnabled
+ */
+ public long getCurrentThreadUserTime();
+
+ /**
+ * Returns the total CPU time for a thread of the specified ID in nanoseconds.
+ * The returned value is of nanoseconds precision but
+ * not necessarily nanoseconds accuracy.
+ * If the implementation distinguishes between user mode time and system
+ * mode time, the returned CPU time is the amount of time that
+ * the thread has executed in user mode or system mode.
+ *
+ * <p>
+ * If the thread of the specified ID is not alive or does not exist,
+ * this method returns <tt>-1</tt>. If CPU time measurement
+ * is disabled, this method returns <tt>-1</tt>.
+ * A thread is alive if it has been started and has not yet died.
+ * <p>
+ * If CPU time measurement is enabled after the thread has started,
+ * the Java virtual machine implementation may choose any time up to
+ * and including the time that the capability is enabled as the point
+ * where CPU time measurement starts.
+ *
+ * @param id the thread ID of a thread
+ * @return the total CPU time for a thread of the specified ID
+ * if the thread of the specified ID exists, the thread is alive,
+ * and CPU time measurement is enabled;
+ * <tt>-1</tt> otherwise.
+ *
+ * @throws IllegalArgumentException if <tt>id <= 0 </tt>.
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support CPU time measurement for
+ * other threads.
+ *
+ * @see #getThreadUserTime
+ * @see #isThreadCpuTimeSupported
+ * @see #isThreadCpuTimeEnabled
+ * @see #setThreadCpuTimeEnabled
+ */
+ public long getThreadCpuTime(long id);
+
+ /**
+ * Returns the CPU time that a thread of the specified ID
+ * has executed in user mode in nanoseconds.
+ * The returned value is of nanoseconds precision but
+ * not necessarily nanoseconds accuracy.
+ *
+ * <p>
+ * If the thread of the specified ID is not alive or does not exist,
+ * this method returns <tt>-1</tt>. If CPU time measurement
+ * is disabled, this method returns <tt>-1</tt>.
+ * A thread is alive if it has been started and has not yet died.
+ * <p>
+ * If CPU time measurement is enabled after the thread has started,
+ * the Java virtual machine implementation may choose any time up to
+ * and including the time that the capability is enabled as the point
+ * where CPU time measurement starts.
+ *
+ * @param id the thread ID of a thread
+ * @return the user-level CPU time for a thread of the specified ID
+ * if the thread of the specified ID exists, the thread is alive,
+ * and CPU time measurement is enabled;
+ * <tt>-1</tt> otherwise.
+ *
+ * @throws IllegalArgumentException if <tt>id <= 0 </tt>.
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support CPU time measurement for
+ * other threads.
+ *
+ * @see #getThreadCpuTime
+ * @see #isThreadCpuTimeSupported
+ * @see #isThreadCpuTimeEnabled
+ * @see #setThreadCpuTimeEnabled
+ */
+ public long getThreadUserTime(long id);
+
+ /**
+ * Tests if the Java virtual machine implementation supports CPU time
+ * measurement for any thread.
+ * A Java virtual machine implementation that supports CPU time
+ * measurement for any thread will also support CPU time
+ * measurement for the current thread.
+ *
+ * @return
+ * <tt>true</tt>
+ * if the Java virtual machine supports CPU time
+ * measurement for any thread;
+ * <tt>false</tt> otherwise.
+ */
+ public boolean isThreadCpuTimeSupported();
+
+ /**
+ * Tests if the Java virtual machine supports CPU time
+ * measurement for the current thread.
+ * This method returns <tt>true</tt> if {@link #isThreadCpuTimeSupported}
+ * returns <tt>true</tt>.
+ *
+ * @return
+ * <tt>true</tt>
+ * if the Java virtual machine supports CPU time
+ * measurement for current thread;
+ * <tt>false</tt> otherwise.
+ */
+ public boolean isCurrentThreadCpuTimeSupported();
+
+ /**
+ * Tests if thread CPU time measurement is enabled.
+ *
+ * @return <tt>true</tt> if thread CPU time measurement is enabled;
+ * <tt>false</tt> otherwise.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java virtual
+ * machine does not support CPU time measurement for other threads
+ * nor for the current thread.
+ *
+ * @see #isThreadCpuTimeSupported
+ * @see #isCurrentThreadCpuTimeSupported
+ */
+ public boolean isThreadCpuTimeEnabled();
+
+ /**
+ * Enables or disables thread CPU time measurement. The default
+ * is platform dependent.
+ *
+ * @param enable <tt>true</tt> to enable;
+ * <tt>false</tt> to disable.
+ *
+ * @throws java.lang.UnsupportedOperationException if the Java
+ * virtual machine does not support CPU time measurement for
+ * any threads nor for the current thread.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("control").
+ *
+ * @see #isThreadCpuTimeSupported
+ * @see #isCurrentThreadCpuTimeSupported
+ */
+ public void setThreadCpuTimeEnabled(boolean enable);
+
+ /**
+ * Finds cycles of threads that are in deadlock waiting to acquire
+ * object monitors. That is, threads that are blocked waiting to enter a
+ * synchronization block or waiting to reenter a synchronization block
+ * after an {@link Object#wait Object.wait} call,
+ * where each thread owns one monitor while
+ * trying to obtain another monitor already held by another thread
+ * in a cycle.
+ * <p>
+ * More formally, a thread is <em>monitor deadlocked</em> if it is
+ * part of a cycle in the relation "is waiting for an object monitor
+ * owned by". In the simplest case, thread A is blocked waiting
+ * for a monitor owned by thread B, and thread B is blocked waiting
+ * for a monitor owned by thread A.
+ * <p>
+ * This method is designed for troubleshooting use, but not for
+ * synchronization control. It might be an expensive operation.
+ * <p>
+ * This method finds deadlocks involving only object monitors.
+ * To find deadlocks involving both object monitors and
+ * <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>,
+ * the {@link #findDeadlockedThreads findDeadlockedThreads} method
+ * should be used.
+ *
+ * @return an array of IDs of the threads that are monitor
+ * deadlocked, if any; <tt>null</tt> otherwise.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ *
+ * @see #findDeadlockedThreads
+ */
+ public long[] findMonitorDeadlockedThreads();
+
+ /**
+ * Resets the peak thread count to the current number of
+ * live threads.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("control").
+ *
+ * @see #getPeakThreadCount
+ * @see #getThreadCount
+ */
+ public void resetPeakThreadCount();
+
+ /**
+ * Finds cycles of threads that are in deadlock waiting to acquire
+ * object monitors or
+ * <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>.
+ *
+ * Threads are <em>deadlocked</em> in a cycle waiting for a lock of
+ * these two types if each thread owns one lock while
+ * trying to acquire another lock already held
+ * by another thread in the cycle.
+ * <p>
+ * This method is designed for troubleshooting use, but not for
+ * synchronization control. It might be an expensive operation.
+ *
+ * @return an array of IDs of the threads that are
+ * deadlocked waiting for object monitors or ownable synchronizers, if any;
+ * <tt>null</tt> otherwise.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ * @throws java.lang.UnsupportedOperationException if the Java virtual
+ * machine does not support monitoriing of ownable synchronizer usage.
+ *
+ * @see #isSynchronizerUsageSupported
+ * @see #findMonitorDeadlockedThreads
+ * @since 1.6
+ */
+ public long[] findDeadlockedThreads();
+
+ /**
+ * Tests if the Java virtual machine supports monitoring of
+ * object monitor usage.
+ *
+ * @return
+ * <tt>true</tt>
+ * if the Java virtual machine supports monitoring of
+ * object monitor usage;
+ * <tt>false</tt> otherwise.
+ *
+ * @see #dumpAllThreads
+ * @since 1.6
+ */
+ public boolean isObjectMonitorUsageSupported();
+
+ /**
+ * Tests if the Java virtual machine supports monitoring of
+ * <a href="LockInfo.html#OwnableSynchronizer">
+ * ownable synchronizer</a> usage.
+ *
+ * @return
+ * <tt>true</tt>
+ * if the Java virtual machine supports monitoring of ownable
+ * synchronizer usage;
+ * <tt>false</tt> otherwise.
+ *
+ * @see #dumpAllThreads
+ * @since 1.6
+ */
+ public boolean isSynchronizerUsageSupported();
+
+ /**
+ * Returns the thread info for each thread
+ * whose ID is in the input array <tt>ids</tt>, with stack trace
+ * and synchronization information.
+ *
+ * <p>
+ * This method obtains a snapshot of the thread information
+ * for each thread including:
+ * <ul>
+ * <li>the entire stack trace,</li>
+ * <li>the object monitors currently locked by the thread
+ * if <tt>lockedMonitors</tt> is <tt>true</tt>, and</li>
+ * <li>the <a href="LockInfo.html#OwnableSynchronizer">
+ * ownable synchronizers</a> currently locked by the thread
+ * if <tt>lockedSynchronizers</tt> is <tt>true</tt>.</li>
+ * </ul>
+ * <p>
+ * This method returns an array of the <tt>ThreadInfo</tt> objects,
+ * each is the thread information about the thread with the same index
+ * as in the <tt>ids</tt> array.
+ * If a thread of the given ID is not alive or does not exist,
+ * <tt>null</tt> will be set in the corresponding element
+ * in the returned array. A thread is alive if
+ * it has been started and has not yet died.
+ * <p>
+ * If a thread does not lock any object monitor or <tt>lockedMonitors</tt>
+ * is <tt>false</tt>, the returned <tt>ThreadInfo</tt> object will have an
+ * empty <tt>MonitorInfo</tt> array. Similarly, if a thread does not
+ * lock any synchronizer or <tt>lockedSynchronizers</tt> is <tt>false</tt>,
+ * the returned <tt>ThreadInfo</tt> object
+ * will have an empty <tt>LockInfo</tt> array.
+ *
+ * <p>
+ * When both <tt>lockedMonitors</tt> and <tt>lockedSynchronizers</tt>
+ * parameters are <tt>false</tt>, it is equivalent to calling:
+ * <blockquote><pre>
+ * {@link #getThreadInfo(long[], int) getThreadInfo(ids, Integer.MAX_VALUE)}
+ * </pre></blockquote>
+ *
+ * <p>
+ * This method is designed for troubleshooting use, but not for
+ * synchronization control. It might be an expensive operation.
+ *
+ * <p>
+ * <b>MBeanServer access</b>:<br>
+ * The mapped type of <tt>ThreadInfo</tt> is
+ * <tt>CompositeData</tt> with attributes as specified in the
+ * {@link ThreadInfo#from ThreadInfo.from} method.
+ *
+ * @param ids an array of thread IDs.
+ * @param lockedMonitors if <tt>true</tt>, retrieves all locked monitors.
+ * @param lockedSynchronizers if <tt>true</tt>, retrieves all locked
+ * ownable synchronizers.
+ *
+ * @return an array of the {@link ThreadInfo} objects, each containing
+ * information about a thread whose ID is in the corresponding
+ * element of the input array of IDs.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ * @throws java.lang.UnsupportedOperationException
+ * <ul>
+ * <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but
+ * the Java virtual machine does not support monitoring
+ * of {@linkplain #isObjectMonitorUsageSupported
+ * object monitor usage}; or</li>
+ * <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but
+ * the Java virtual machine does not support monitoring
+ * of {@linkplain #isSynchronizerUsageSupported
+ * ownable synchronizer usage}.</li>
+ * </ul>
+ *
+ * @see #isObjectMonitorUsageSupported
+ * @see #isSynchronizerUsageSupported
+ *
+ * @since 1.6
+ */
+ public ThreadInfo[] getThreadInfo(long[] ids, boolean lockedMonitors, boolean lockedSynchronizers);
+
+ /**
+ * Returns the thread info for all live threads with stack trace
+ * and synchronization information.
+ * Some threads included in the returned array
+ * may have been terminated when this method returns.
+ *
+ * <p>
+ * This method returns an array of {@link ThreadInfo} objects
+ * as specified in the {@link #getThreadInfo(long[], boolean, boolean)}
+ * method.
+ *
+ * @param lockedMonitors if <tt>true</tt>, dump all locked monitors.
+ * @param lockedSynchronizers if <tt>true</tt>, dump all locked
+ * ownable synchronizers.
+ *
+ * @return an array of {@link ThreadInfo} for all live threads.
+ *
+ * @throws java.lang.SecurityException if a security manager
+ * exists and the caller does not have
+ * ManagementPermission("monitor").
+ * @throws java.lang.UnsupportedOperationException
+ * <ul>
+ * <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but
+ * the Java virtual machine does not support monitoring
+ * of {@linkplain #isObjectMonitorUsageSupported
+ * object monitor usage}; or</li>
+ * <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but
+ * the Java virtual machine does not support monitoring
+ * of {@linkplain #isSynchronizerUsageSupported
+ * ownable synchronizer usage}.</li>
+ * </ul>
+ *
+ * @see #isObjectMonitorUsageSupported
+ * @see #isSynchronizerUsageSupported
+ *
+ * @since 1.6
+ */
+ public ThreadInfo[] dumpAllThreads(boolean lockedMonitors, boolean lockedSynchronizers);
+}