Java tutorial
/* * Copyright (c) 2003, 2019, 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 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 MBeanServer} method. * * <p>The {@code ObjectName} for uniquely identifying the MXBean for * the thread system within an MBeanServer is: * <blockquote> * {@link ManagementFactory#THREAD_MXBEAN_NAME * java.lang:type=Threading} * </blockquote> * * It can be obtained by calling the * {@link PlatformManagedObject#getObjectName} method. * * <h2>Thread ID</h2> * 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. * * <h2>Thread CPU time</h2> * 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. * * <h2>Thread Contention Monitoring</h2> * 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">{@code ThreadInfo}</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. * * <h2>Synchronization Information and Deadlock Detection</h2> * 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 {@code ThreadMXBean} interface provides the * {@link #findMonitorDeadlockedThreads} and * {@link #findDeadlockedThreads} methods to find deadlocks in * the running application. * * @see ManagementFactory#getPlatformMXBeans(Class) * @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 extends PlatformManagedObject { /** * 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 {@code long}, 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 * {@code id} with no stack trace. * This method is equivalent to calling: * <blockquote> * {@link #getThreadInfo(long, int) getThreadInfo(id, 0);} * </blockquote> * * <p> * This method returns a {@code ThreadInfo} object representing * the thread information for the thread of the specified ID. * The stack trace, locked monitors, and locked synchronizers * in the returned {@code ThreadInfo} object will * be empty. * * If a thread of the given ID is not alive or does not exist, * this method will return {@code null}. A thread is alive if * it has been started and has not yet died. * * <p> * <b>MBeanServer access</b>:<br> * The mapped type of {@code ThreadInfo} is * {@code CompositeData} 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; * {@code null} if the thread of the given ID is not alive or * it does not exist. * * @throws IllegalArgumentException if {@code id <= 0}. * @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 {@code ids} 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 {@code ThreadInfo} objects. * The stack trace, locked monitors, and locked synchronizers * in each {@code ThreadInfo} 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 {@code null}. A thread is alive if * it has been started and has not yet died. * * <p> * <b>MBeanServer access</b>:<br> * The mapped type of {@code ThreadInfo} is * {@code CompositeData} 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 * {@code ids} is {@code <= 0}. * @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 {@code id}, * with stack trace of a specified number of stack trace elements. * The {@code maxDepth} parameter indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * If {@code maxDepth == Integer.MAX_VALUE}, the entire stack trace of * the thread will be dumped. * If {@code maxDepth == 0}, 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 {@code maxDepth == 0}, * the stack trace in the * {@code ThreadInfo} object will be an empty array of * {@code StackTraceElement}. * * <p> * If a thread of the given ID is not alive or does not exist, * this method will return {@code null}. A thread is alive if * it has been started and has not yet died. * * <p> * <b>MBeanServer access</b>:<br> * The mapped type of {@code ThreadInfo} is * {@code CompositeData} 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. {@code Integer.MAX_VALUE} 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. * {@code null} if the thread of the given ID is not alive or * it does not exist. * * @throws IllegalArgumentException if {@code id <= 0}. * @throws IllegalArgumentException if {@code maxDepth is negative}. * @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 {@code ids}, * with stack trace of a specified number of stack trace elements. * The {@code maxDepth} parameter indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * If {@code maxDepth == Integer.MAX_VALUE}, the entire stack trace of * the thread will be dumped. * If {@code maxDepth == 0}, 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 {@code maxDepth == 0}, * the stack trace in the * {@code ThreadInfo} object will be an empty array of * {@code StackTraceElement}. * <p> * This method returns an array of the {@code ThreadInfo} objects, * each is the thread information about the thread with the same index * as in the {@code ids} array. * If a thread of the given ID is not alive or does not exist, * {@code null} 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 {@code ThreadInfo} is * {@code CompositeData} 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. {@code Integer.MAX_VALUE} 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 {@code maxDepth is negative}. * @throws IllegalArgumentException if any element in the input array * {@code ids} is {@code <= 0}. * @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 * {@code true} * if the Java virtual machine supports thread contention monitoring; * {@code false} otherwise. */ public boolean isThreadContentionMonitoringSupported(); /** * Tests if thread contention monitoring is enabled. * * @return {@code true} if thread contention monitoring is enabled; * {@code false} 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 {@code true} to enable; * {@code false} 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; {@code -1} 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; {@code -1} 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 {@code -1}. If CPU time measurement * is disabled, this method returns {@code -1}. * 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; * {@code -1} otherwise. * * @throws IllegalArgumentException if {@code id <= 0}. * @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 {@code -1}. If CPU time measurement * is disabled, this method returns {@code -1}. * 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; * {@code -1} otherwise. * * @throws IllegalArgumentException if {@code id <= 0}. * @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 * {@code true} * if the Java virtual machine supports CPU time * measurement for any thread; * {@code false} otherwise. */ public boolean isThreadCpuTimeSupported(); /** * Tests if the Java virtual machine supports CPU time * measurement for the current thread. * This method returns {@code true} if {@link #isThreadCpuTimeSupported} * returns {@code true}. * * @return * {@code true} * if the Java virtual machine supports CPU time * measurement for current thread; * {@code false} otherwise. */ public boolean isCurrentThreadCpuTimeSupported(); /** * Tests if thread CPU time measurement is enabled. * * @return {@code true} if thread CPU time measurement is enabled; * {@code false} 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 {@code true} to enable; * {@code false} 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; {@code null} 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; * {@code null} 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 monitoring 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 * {@code true} * if the Java virtual machine supports monitoring of * object monitor usage; * {@code false} 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 * {@code true} * if the Java virtual machine supports monitoring of ownable * synchronizer usage; * {@code false} otherwise. * * @see #dumpAllThreads * @since 1.6 */ public boolean isSynchronizerUsageSupported(); /** * Returns the thread info for each thread * whose ID is in the input array {@code ids}, * with stack trace and synchronization information. * This is equivalent to calling: * <blockquote> * {@link #getThreadInfo(long[], boolean, boolean, int) * getThreadInfo(ids, lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE)} * </blockquote> * * @param ids an array of thread IDs. * @param lockedMonitors if {@code true}, retrieves all locked monitors. * @param lockedSynchronizers if {@code true}, 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 {@code lockedMonitors} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if {@code lockedSynchronizers} is {@code true} 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 each thread whose ID * is in the input array {@code ids}, * with stack trace of the specified maximum number of elements * and synchronization information. * If {@code maxDepth == 0}, no stack trace of the thread * will be dumped. * * <p> * This method obtains a snapshot of the thread information * for each thread including: * <ul> * <li>stack trace of the specified maximum number of elements,</li> * <li>the object monitors currently locked by the thread * if {@code lockedMonitors} is {@code true}, and</li> * <li>the <a href="LockInfo.html#OwnableSynchronizer"> * ownable synchronizers</a> currently locked by the thread * if {@code lockedSynchronizers} is {@code true}.</li> * </ul> * <p> * This method returns an array of the {@code ThreadInfo} objects, * each is the thread information about the thread with the same index * as in the {@code ids} array. * If a thread of the given ID is not alive or does not exist, * {@code null} 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 {@code lockedMonitors} * is {@code false}, the returned {@code ThreadInfo} object will have an * empty {@code MonitorInfo} array. Similarly, if a thread does not * lock any synchronizer or {@code lockedSynchronizers} is {@code false}, * the returned {@code ThreadInfo} object * will have an empty {@code LockInfo} array. * * <p> * When both {@code lockedMonitors} and {@code lockedSynchronizers} * parameters are {@code false}, it is equivalent to calling: * <blockquote><pre> * {@link #getThreadInfo(long[], int) getThreadInfo(ids, maxDepth)} * </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 {@code ThreadInfo} is * {@code CompositeData} with attributes as specified in the * {@link ThreadInfo#from ThreadInfo.from} method. * * @implSpec The default implementation throws * {@code UnsupportedOperationException}. * * @param ids an array of thread IDs. * @param lockedMonitors if {@code true}, retrieves all locked monitors. * @param lockedSynchronizers if {@code true}, retrieves all locked * ownable synchronizers. * @param maxDepth indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * * @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 IllegalArgumentException if {@code maxDepth} is negative. * @throws java.lang.SecurityException if a security manager * exists and the caller does not have * ManagementPermission("monitor"). * @throws java.lang.UnsupportedOperationException * <ul> * <li>if {@code lockedMonitors} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if {@code lockedSynchronizers} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isSynchronizerUsageSupported * ownable synchronizer usage}.</li> * </ul> * * @see #isObjectMonitorUsageSupported * @see #isSynchronizerUsageSupported * * @since 10 */ public default ThreadInfo[] getThreadInfo(long[] ids, boolean lockedMonitors, boolean lockedSynchronizers, int maxDepth) { throw new UnsupportedOperationException(); } /** * Returns the thread info for all live threads with stack trace * and synchronization information. * This is equivalent to calling: * <blockquote> * {@link #dumpAllThreads(boolean, boolean, int) * dumpAllThreads(lockedMonitors, lockedSynchronizers, Integer.MAX_VALUE)} * </blockquote> * * @param lockedMonitors if {@code true}, dump all locked monitors. * @param lockedSynchronizers if {@code true}, 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 {@code lockedMonitors} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if {@code lockedSynchronizers} is {@code true} 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); /** * Returns the thread info for all live threads * with stack trace of the specified maximum number of elements * and synchronization information. * if {@code maxDepth == 0}, no stack trace of the thread * will be dumped. * 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, int)} * method. * * @implSpec The default implementation throws * {@code UnsupportedOperationException}. * * @param lockedMonitors if {@code true}, dump all locked monitors. * @param lockedSynchronizers if {@code true}, dump all locked * ownable synchronizers. * @param maxDepth indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * * @return an array of {@link ThreadInfo} for all live threads. * * @throws IllegalArgumentException if {@code maxDepth} is negative. * @throws java.lang.SecurityException if a security manager * exists and the caller does not have * ManagementPermission("monitor"). * @throws java.lang.UnsupportedOperationException * <ul> * <li>if {@code lockedMonitors} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if {@code lockedSynchronizers} is {@code true} but * the Java virtual machine does not support monitoring * of {@linkplain #isSynchronizerUsageSupported * ownable synchronizer usage}.</li> * </ul> * * @see #isObjectMonitorUsageSupported * @see #isSynchronizerUsageSupported * * @since 10 */ public default ThreadInfo[] dumpAllThreads(boolean lockedMonitors, boolean lockedSynchronizers, int maxDepth) { throw new UnsupportedOperationException(); } }