Class ThreadInfo
- 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.
- Whether a thread is a daemon 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.
- Thread priority
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 a CompositeData
with attributes as specified in the from
method.- Since:
- 1.5
- See Also:
-
ThreadMXBean.getThreadInfo(long)
,ThreadMXBean.dumpAllThreads(boolean, boolean)
Method Summary
Modifier and Type | Method | Description |
---|---|---|
static ThreadInfo | from(CompositeData cd) | Returns a |
long | getBlockedCount() | Returns the total number of times that the thread associated with this |
long | getBlockedTime() | Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this |
MonitorInfo[] | getLockedMonitors() | Returns an array of |
LockInfo[] | getLockedSynchronizers() | Returns an array of |
LockInfo | getLockInfo() | Returns the |
String | getLockName() | Returns the |
long | getLockOwnerId() | Returns the ID of the thread which owns the object for which the thread associated with this |
String | getLockOwnerName() | Returns the name of the thread which owns the object for which the thread associated with this |
int | getPriority() | Returns the thread priority of the thread associated with this |
StackTraceElement[] | getStackTrace() | Returns the stack trace of the thread associated with this |
long | getThreadId() | Returns the ID of the thread associated with this |
String | getThreadName() | Returns the name of the thread associated with this |
Thread.State | getThreadState() | Returns the state of the thread associated with this |
long | getWaitedCount() | Returns the total number of times that the thread associated with this |
long | getWaitedTime() | Returns the approximate accumulated elapsed time (in milliseconds) that the thread associated with this |
boolean | isDaemon() | Tests if the thread associated with this |
boolean | isInNative() | Tests if the thread associated with this |
boolean | isSuspended() | Tests if the thread associated with this |
String | toString() | Returns a string representation of this thread info. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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 the BLOCKED
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 the BLOCKED
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 the WAITING
or TIMED_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
orTIMED_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 the WAITING
or TIMED_WAITING
state.
- Returns:
- the total number of times that the thread was in the
WAITING
orTIMED_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 thesynchronized
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
getLockName
public String getLockName()
Returns the string 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 is 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
if Thread.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.
isDaemon
public boolean isDaemon()
Tests if the thread associated with this ThreadInfo
is a daemon thread.
- Returns:
-
true
if the thread is a daemon thread,false
otherwise. - Since:
- 9
- See Also:
Thread.isDaemon()
getPriority
public int getPriority()
Returns the thread priority of the thread associated with this ThreadInfo
.
- Returns:
- The priority of the thread associated with this
ThreadInfo
. - Since:
- 9
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
. A CompositeData
representing a ThreadInfo
of version N must contain all of the attributes defined in version ≤ N unless specified otherwise. The same rule applies the composite type of the given CompositeData
and transitively to attributes whose type or component type is CompositeType
.
A CompositeData
representing ThreadInfo
of version N contains "stackTrace"
attribute and "lockedMonitors"
attribute representing an array of StackTraceElement
and an array of MonitorInfo
respectively and their types are of version N. The "lockedStackFrame"
attribute in MonitorInfo
's composite type must represent StackTraceElement
of the same version N. Otherwise, this method will throw IllegalArgumentException
.
Attribute Name | Type | Since |
---|---|---|
threadId | java.lang.Long | 5 |
threadName | java.lang.String | 5 |
threadState | java.lang.String | 5 |
suspended | java.lang.Boolean | 5 |
inNative | java.lang.Boolean | 5 |
blockedCount | java.lang.Long | 5 |
blockedTime | java.lang.Long | 5 |
waitedCount | java.lang.Long | 5 |
waitedTime | java.lang.Long | 5 |
lockName | java.lang.String | 5 |
lockOwnerId | java.lang.Long | 5 |
lockOwnerName | java.lang.String | 5 |
stackTrace |
javax.management.openmbean.CompositeData[] , each element is a CompositeData representing StackTraceElement as specified below. | 5 |
lockInfo |
javax.management.openmbean.CompositeData - the mapped type for LockInfo as specified in the LockInfo.from(javax.management.openmbean.CompositeData) method. If the given | 6 |
lockedMonitors |
javax.management.openmbean.CompositeData[] whose element type is the mapped type for MonitorInfo as specified in the MonitorInfo.from method. If the given | 6 |
lockedSynchronizers |
javax.management.openmbean.CompositeData[] whose element type is the mapped type for LockInfo as specified in the LockInfo.from(javax.management.openmbean.CompositeData) method. If the given | 6 |
daemon |
java.lang.Boolean If the given | 9 |
priority |
java.lang.Integer If the given | 9 |
CompositeData
representing StackTraceElement
of version N must contain all of the attributes defined in version ≤ N unless specified otherwise. Attribute Name | Type | Since |
---|---|---|
classLoaderName | java.lang.String | 9 |
moduleName | java.lang.String | 9 |
moduleVersion | java.lang.String | 9 |
className | java.lang.String | 5 |
methodName | java.lang.String | 5 |
fileName | java.lang.String | 5 |
lineNumber | java.lang.Integer | 5 |
nativeMethod | java.lang.Boolean | 5 |
- Parameters:
-
cd
-CompositeData
representing aThreadInfo
- Returns:
- a
ThreadInfo
object represented bycd
ifcd
is notnull
;null
otherwise. - Throws:
-
IllegalArgumentException
- if the givencd
and its composite type does not contain all of the attributes defined for aThreadInfo
of a specific runtime version.
getLockedMonitors
public MonitorInfo[] getLockedMonitors()
Returns an array of MonitorInfo
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 of LockInfo
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