- java.lang.Object
-
- java.lang.management.ThreadInfo
-
public class ThreadInfo extends Object
Thread information. ThreadInfo contains the information about a thread including:General thread information
- Thread ID.
- Name of the thread.
Execution information
- Thread state.
- The object upon which the thread is blocked due to:
- waiting to enter a synchronization block/method, or
- waiting to be notified in a
Object.wait
method, or - parking due to a
LockSupport.park
call.
- The ID of the thread that owns the object that the thread is blocked.
- Stack trace of the thread.
- List of object monitors locked by the thread.
- List of ownable synchronizers locked by the thread.
Synchronization Statistics
- The number of times that the thread has blocked for synchronization or waited for notification.
- The accumulated elapsed time that the thread has blocked
for synchronization or waited for notification
since
thread contention monitoring
was enabled. Some Java virtual machine implementation may not support this. TheThreadMXBean.isThreadContentionMonitoringSupported()
method can be used to determine if a Java virtual machine supports this.
This thread information class is designed for use in monitoring of the system, not for synchronization control.
MXBean Mapping
ThreadInfo is mapped to aCompositeData
with attributes as specified in thefrom
method.- Since:
- 1.5
- See Also:
ThreadMXBean.getThreadInfo(long)
,ThreadMXBean.dumpAllThreads(boolean, boolean)
-
-
Method Summary
Methods Modifier and Type Method and Description static ThreadInfo
from(CompositeData cd)
Returns a ThreadInfo object represented by the given CompositeData.long
getBlockedCount()
Returns the total number of times that the thread associated with this ThreadInfo blocked to enter or reenter a monitor.long
getBlockedTime()
Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this ThreadInfo has blocked to enter or reenter a monitor since thread contention monitoring is enabled.MonitorInfo[]
getLockedMonitors()
Returns an array ofMonitorInfo
objects, each of which represents an object monitor currently locked by the thread associated with this ThreadInfo.LockInfo[]
getLockedSynchronizers()
Returns an array ofLockInfo
objects, each of which represents an ownable synchronizer currently locked by the thread associated with this ThreadInfo.LockInfo
getLockInfo()
Returns the LockInfo of an object for which the thread associated with this ThreadInfo is blocked waiting.String
getLockName()
Returns thestring representation
of an object for which the thread associated with this ThreadInfo is blocked waiting.long
getLockOwnerId()
Returns the ID of the thread which owns the object for which the thread associated with this ThreadInfo is blocked waiting.String
getLockOwnerName()
Returns the name of the thread which owns the object for which the thread associated with this ThreadInfo is blocked waiting.StackTraceElement[]
getStackTrace()
Returns the stack trace of the thread associated with this ThreadInfo.long
getThreadId()
Returns the ID of the thread associated with this ThreadInfo.String
getThreadName()
Returns the name of the thread associated with this ThreadInfo.Thread.State
getThreadState()
Returns the state of the thread associated with this ThreadInfo.long
getWaitedCount()
Returns the total number of times that the thread associated with this ThreadInfo waited for notification.long
getWaitedTime()
Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this ThreadInfo has waited for notification since thread contention monitoring is enabled.boolean
isInNative()
Tests if the thread associated with this ThreadInfo is executing native code via the Java Native Interface (JNI).boolean
isSuspended()
Tests if the thread associated with this ThreadInfo is suspended.String
toString()
Returns a string representation of this thread info.
-
-
-
Method Detail
-
getThreadId
public long getThreadId()
Returns the ID of the thread associated with this ThreadInfo.- Returns:
- the ID of the associated thread.
-
getThreadName
public String getThreadName()
Returns the name of the thread associated with this ThreadInfo.- Returns:
- the name of the associated thread.
-
getThreadState
public Thread.State getThreadState()
Returns the state of the thread associated with this ThreadInfo.- Returns:
- Thread.State of the associated thread.
-
getBlockedTime
public long getBlockedTime()
Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this ThreadInfo has blocked to enter or reenter a monitor since thread contention monitoring is enabled. I.e. the total accumulated time the thread has been in theBLOCKED
state since thread contention monitoring was last enabled. This method returns -1 if thread contention monitoring is disabled.The Java virtual machine may measure the time with a high resolution timer. This statistic is reset when the thread contention monitoring is reenabled.
- Returns:
- the approximate accumulated elapsed time in milliseconds that a thread entered the BLOCKED state; -1 if thread contention monitoring is disabled.
- Throws:
UnsupportedOperationException
- if the Java virtual machine does not support this operation.- See Also:
ThreadMXBean.isThreadContentionMonitoringSupported()
,ThreadMXBean.setThreadContentionMonitoringEnabled(boolean)
-
getBlockedCount
public long getBlockedCount()
Returns the total number of times that the thread associated with this ThreadInfo blocked to enter or reenter a monitor. I.e. the number of times a thread has been in theBLOCKED
state.- Returns:
- the total number of times that the thread entered the BLOCKED state.
-
getWaitedTime
public long getWaitedTime()
Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this ThreadInfo has waited for notification since thread contention monitoring is enabled. I.e. the total accumulated time the thread has been in theWAITING
orTIMED_WAITING
state since thread contention monitoring is enabled. This method returns -1 if thread contention monitoring is disabled.The Java virtual machine may measure the time with a high resolution timer. This statistic is reset when the thread contention monitoring is reenabled.
- Returns:
- the approximate accumulated elapsed time in milliseconds that a thread has been in the WAITING or TIMED_WAITING state; -1 if thread contention monitoring is disabled.
- Throws:
UnsupportedOperationException
- if the Java virtual machine does not support this operation.- See Also:
ThreadMXBean.isThreadContentionMonitoringSupported()
,ThreadMXBean.setThreadContentionMonitoringEnabled(boolean)
-
getWaitedCount
public long getWaitedCount()
Returns the total number of times that the thread associated with this ThreadInfo waited for notification. I.e. the number of times that a thread has been in theWAITING
orTIMED_WAITING
state.- Returns:
- the total number of times that the thread was in the WAITING or TIMED_WAITING state.
-
getLockInfo
public LockInfo getLockInfo()
Returns the LockInfo of an object for which the thread associated with this ThreadInfo is blocked waiting. A thread can be blocked waiting for one of the following:- an object monitor to be acquired for entering or reentering
a synchronization block/method.
The thread is in theBLOCKED
state waiting to enter the synchronized statement or method. - an object monitor to be notified by another thread.
The thread is in theWAITING
orTIMED_WAITING
state due to a call to theObject.wait
method. - a synchronization object responsible for the thread parking.
The thread is in theWAITING
orTIMED_WAITING
state due to a call to theLockSupport.park
method. The synchronization object is the object returned fromLockSupport.getBlocker
method. Typically it is an ownable synchronizer or aCondition
.
This method returns null if the thread is not in any of the above conditions.
- Returns:
- LockInfo of an object for which the thread is blocked waiting if any; null otherwise.
- Since:
- 1.6
- an object monitor to be acquired for entering or reentering
a synchronization block/method.
-
getLockName
public String getLockName()
Returns thestring representation
of an object for which the thread associated with this ThreadInfo is blocked waiting. This method is equivalent to calling:getLockInfo().toString()
This method will return null if this thread is not blocked waiting for any object or if the object is not owned by any thread.
- Returns:
- the string representation of the object on which the thread is blocked if any; null otherwise.
- See Also:
getLockInfo()
-
getLockOwnerId
public long getLockOwnerId()
Returns the ID of the thread which owns the object for which the thread associated with this ThreadInfo is blocked waiting. This method will return -1 if this thread is not blocked waiting for any object or if the object is not owned by any thread.- Returns:
- the thread ID of the owner thread of the object this thread is blocked on; -1 if this thread is not blocked or if the object lis not owned by any thread.
- See Also:
getLockInfo()
-
getLockOwnerName
public String getLockOwnerName()
Returns the name of the thread which owns the object for which the thread associated with this ThreadInfo is blocked waiting. This method will return null if this thread is not blocked waiting for any object or if the object is not owned by any thread.- Returns:
- the name of the thread that owns the object this thread is blocked on; null if this thread is not blocked or if the object is not owned by any thread.
- See Also:
getLockInfo()
-
getStackTrace
public StackTraceElement[] getStackTrace()
Returns the stack trace of the thread associated with this ThreadInfo. If no stack trace was requested for this thread info, this method will return a zero-length array. If the returned array is of non-zero length then the first element of the array represents the top of the stack, which is the most recent method invocation in the sequence. The last element of the array represents the bottom of the stack, which is the least recent method invocation in the sequence.Some Java virtual machines may, under some circumstances, omit one or more stack frames from the stack trace. In the extreme case, a virtual machine that has no stack trace information concerning the thread associated with this ThreadInfo is permitted to return a zero-length array from this method.
- Returns:
- an array of StackTraceElement objects of the thread.
-
isSuspended
public boolean isSuspended()
Tests if the thread associated with this ThreadInfo is suspended. This method returns true ifThread.suspend()
has been called.- Returns:
- true if the thread is suspended; false otherwise.
-
isInNative
public boolean isInNative()
Tests if the thread associated with this ThreadInfo is executing native code via the Java Native Interface (JNI). The JNI native code does not include the virtual machine support code or the compiled native code generated by the virtual machine.- Returns:
- true if the thread is executing native code; false otherwise.
-
toString
public String toString()
Returns a string representation of this thread info. The format of this string depends on the implementation. The returned string will typically include the thread name, the thread ID, its state, and a stack trace if any.
-
from
public static ThreadInfo from(CompositeData cd)
Returns a ThreadInfo object represented by the given CompositeData. The given CompositeData must contain the following attributes unless otherwise specified below:Attribute Name Type threadId java.lang.Long threadName java.lang.String threadState java.lang.String suspended java.lang.Boolean inNative java.lang.Boolean blockedCount java.lang.Long blockedTime java.lang.Long waitedCount java.lang.Long waitedTime java.lang.Long lockInfo javax.management.openmbean.CompositeData - the mapped type for LockInfo
as specified in the type mapping rules of MXBeans.If cd does not contain this attribute, the LockInfo object will be constructed from the value of the lockName attribute.
lockName java.lang.String lockOwnerId java.lang.Long lockOwnerName java.lang.String stackTrace javax.management.openmbean.CompositeData[] Each element is a CompositeData representing StackTraceElement containing the following attributes:
Attribute Name Type className java.lang.String methodName java.lang.String fileName java.lang.String lineNumber java.lang.Integer nativeMethod java.lang.Boolean lockedMonitors javax.management.openmbean.CompositeData[] whose element type is the mapped type for MonitorInfo
as specified in theMonitor.from
method.If cd does not contain this attribute, this attribute will be set to an empty array.
lockedSynchronizers javax.management.openmbean.CompositeData[] whose element type is the mapped type for LockInfo
as specified in the type mapping rules of MXBeans.If cd does not contain this attribute, this attribute will be set to an empty array.
- Parameters:
cd
- CompositeData representing a ThreadInfo- Returns:
- a ThreadInfo object represented by cd if cd is not null; null otherwise.
- Throws:
IllegalArgumentException
- if cd does not represent a ThreadInfo with the attributes described above.
-
getLockedMonitors
public MonitorInfo[] getLockedMonitors()
Returns an array ofMonitorInfo
objects, each of which represents an object monitor currently locked by the thread associated with this ThreadInfo. If no locked monitor was requested for this thread info or no monitor is locked by the thread, this method will return a zero-length array.- Returns:
- an array of MonitorInfo objects representing the object monitors locked by the thread.
- Since:
- 1.6
-
getLockedSynchronizers
public LockInfo[] getLockedSynchronizers()
Returns an array ofLockInfo
objects, each of which represents an ownable synchronizer currently locked by the thread associated with this ThreadInfo. If no locked synchronizer was requested for this thread info or no synchronizer is locked by the thread, this method will return a zero-length array.- Returns:
- an array of LockInfo objects representing the ownable synchronizers locked by the thread.
- Since:
- 1.6
-
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Dokument erstellt 11/06/2005, zuletzt geändert 04/03/2020
Quelle des gedruckten Dokuments:https://www.gaudry.be/de/java-api-rf-java/lang/management/ThreadInfo.html
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