alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (ThreadMXBean.java)

This example Java source code file (ThreadMXBean.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

platformmanagedobject, threadinfo, threadmxbean, util

The ThreadMXBean.java Java example source code

/*
 * Copyright (c) 2003, 2013, 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
 * that can be obtained by calling
 * the {@link ManagementFactory#getThreadMXBean} method or
 * from the {@link ManagementFactory#getPlatformMBeanServer
 * platform <tt>MBeanServer} method.
 *
 * <p>The ObjectName for uniquely identifying the MXBean for
 * the thread system within an MBeanServer is:
 * <blockquote>
 *    {@link ManagementFactory#THREAD_MXBEAN_NAME
 *           <tt>java.lang:type=Threading}
 * </blockquote>
 *
 * It can be obtained by calling the
 * {@link PlatformManagedObject#getObjectName} method.
 *
 * <h3>Thread ID
 * 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.
 *
 * <h3>Thread CPU time
 * 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.
 *
 * <h3>Thread Contention Monitoring
 * 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">ThreadInfo 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.
 *
 * <h3>Synchronization Information and Deadlock Detection
 * 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} a thread is blocked to
 * acquire or waiting on and which locks the thread currently owns.
 * <p>
 * The <tt>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 <tt>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
     * <tt>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 <tt>ThreadInfo 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 object will
     * be empty.
     *
     * If a thread of the given ID is not alive or does not exist,
     * this method will return <tt>null.  A thread is alive if
     * it has been started and has not yet died.
     *
     * <p>
     * <b>MBeanServer access:
* The mapped type of <tt>ThreadInfo is * <tt>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; * <tt>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 <tt>ids with no stack trace. * This method is equivalent to calling: * <blockquote>
     *   {@link #getThreadInfo(long[], int) getThreadInfo}(ids, 0);
     * </pre>
     *
     * <p>
     * This method returns an array of the <tt>ThreadInfo objects.
     * The stack trace, locked monitors, and locked synchronizers
     * in each <tt>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 <tt>null.  A thread is alive if
     * it has been started and has not yet died.
     *
     * <p>
     * <b>MBeanServer access:
* The mapped type of <tt>ThreadInfo is * <tt>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 * <tt>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 <tt>id, * with stack trace of a specified number of stack trace elements. * The <tt>maxDepth parameter indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * If <tt>maxDepth == Integer.MAX_VALUE, the entire stack trace of * the thread will be dumped. * If <tt>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 <tt>maxDepth == 0, * the stack trace in the * <tt>ThreadInfo object will be an empty array of * <tt>StackTraceElement. * * <p> * If a thread of the given ID is not alive or does not exist, * this method will return <tt>null. A thread is alive if * it has been started and has not yet died. * * <p> * <b>MBeanServer access:
* The mapped type of <tt>ThreadInfo is * <tt>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. <tt>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. * <tt>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 <tt>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 <tt>ids, * with stack trace of a specified number of stack trace elements. * The <tt>maxDepth parameter indicates the maximum number of * {@link StackTraceElement} to be retrieved from the stack trace. * If <tt>maxDepth == Integer.MAX_VALUE, the entire stack trace of * the thread will be dumped. * If <tt>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 <tt>maxDepth == 0, * the stack trace in the * <tt>ThreadInfo object will be an empty array of * <tt>StackTraceElement. * <p> * This method returns an array of the <tt>ThreadInfo objects, * each is the thread information about the thread with the same index * as in the <tt>ids array. * If a thread of the given ID is not alive or does not exist, * <tt>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:
* The mapped type of <tt>ThreadInfo is * <tt>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. <tt>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 <tt>maxDepth is negative. * @throws IllegalArgumentException if any element in the input array * <tt>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 * <tt>true * if the Java virtual machine supports thread contention monitoring; * <tt>false otherwise. */ public boolean isThreadContentionMonitoringSupported(); /** * Tests if thread contention monitoring is enabled. * * @return <tt>true if thread contention monitoring is enabled; * <tt>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 <tt>true to enable; * <tt>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>
     *   {@link #getThreadCpuTime getThreadCpuTime}(Thread.currentThread().getId());
     * </pre>
     *
     * @return the total CPU time for the current thread if CPU time
     * measurement is enabled; <tt>-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>
     *   {@link #getThreadUserTime getThreadUserTime}(Thread.currentThread().getId());
     * </pre>
     *
     * @return the user-level CPU time for the current thread if CPU time
     * measurement is enabled; <tt>-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 <tt>-1. If CPU time measurement
     * is disabled, this method returns <tt>-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;
     * <tt>-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 <tt>-1. If CPU time measurement
     * is disabled, this method returns <tt>-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;
     * <tt>-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
     *   <tt>true
     *     if the Java virtual machine supports CPU time
     *     measurement for any thread;
     *   <tt>false otherwise.
     */
    public boolean isThreadCpuTimeSupported();

    /**
     * Tests if the Java virtual machine supports CPU time
     * measurement for the current thread.
     * This method returns <tt>true if {@link #isThreadCpuTimeSupported}
     * returns <tt>true.
     *
     * @return
     *   <tt>true
     *     if the Java virtual machine supports CPU time
     *     measurement for current thread;
     *   <tt>false otherwise.
     */
    public boolean isCurrentThreadCpuTimeSupported();

    /**
     * Tests if thread CPU time measurement is enabled.
     *
     * @return <tt>true if thread CPU time measurement is enabled;
     *         <tt>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 <tt>true to enable;
     *               <tt>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 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,
     * the {@link #findDeadlockedThreads findDeadlockedThreads} method
     * should be used.
     *
     * @return an array of IDs of the threads that are monitor
     * deadlocked, if any; <tt>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.
     *
     * Threads are <em>deadlocked 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 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
     *   <tt>true
     *     if the Java virtual machine supports monitoring of
     *     object monitor usage;
     *   <tt>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
     *   <tt>true
     *     if the Java virtual machine supports monitoring of ownable
     *     synchronizer usage;
     *   <tt>false 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, 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>the object monitors currently locked by the thread
     *        if <tt>lockedMonitors is true, and
     *    <li>the 
     *        ownable synchronizers</a> currently locked by the thread
     *        if <tt>lockedSynchronizers is true.
     * </ul>
     * <p>
     * This method returns an array of the <tt>ThreadInfo objects,
     * each is the thread information about the thread with the same index
     * as in the <tt>ids array.
     * If a thread of the given ID is not alive or does not exist,
     * <tt>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 <tt>lockedMonitors
     * is <tt>false, the returned ThreadInfo object will have an
     * empty <tt>MonitorInfo array.  Similarly, if a thread does not
     * lock any synchronizer or <tt>lockedSynchronizers is false,
     * the returned <tt>ThreadInfo object
     * will have an empty <tt>LockInfo array.
     *
     * <p>
     * When both <tt>lockedMonitors and lockedSynchronizers
     * parameters are <tt>false, it is equivalent to calling:
     * <blockquote>
     *     {@link #getThreadInfo(long[], int)  getThreadInfo(ids, Integer.MAX_VALUE)}
     * </pre>
     *
     * <p>
     * This method is designed for troubleshooting use, but not for
     * synchronization control.  It might be an expensive operation.
     *
     * <p>
     * <b>MBeanServer access:
* The mapped type of <tt>ThreadInfo is * <tt>CompositeData with attributes as specified in the * {@link ThreadInfo#from ThreadInfo.from} method. * * @param ids an array of thread IDs. * @param lockedMonitors if <tt>true, retrieves all locked monitors. * @param lockedSynchronizers if <tt>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 lockedMonitors is true but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if lockedSynchronizers is 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 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, dump all locked monitors. * @param lockedSynchronizers if <tt>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 lockedMonitors is true but * the Java virtual machine does not support monitoring * of {@linkplain #isObjectMonitorUsageSupported * object monitor usage}; or</li> * <li>if lockedSynchronizers is 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); }
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.