OpenJDK 27 · com.sun.management.ThreadMXBean · APIdia, the JavaDoc alternative

Method Summary

Modifier and Type	Method and Description
public default long	Returns: an approximation of the total memory allocated, in bytes, in heap memory for the current thread if thread memory allocation measurement is enabled; `-1` otherwise. getCurrentThreadAllocatedBytes() Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the current thread.
public long	Returns: an approximation of the total memory allocated, in bytes, in heap memory for the thread with the specified ID if the thread with the specified ID is a platform thread, the thread is alive, and thread memory allocation measurement is enabled; `-1` otherwise. getThreadAllocatedBytes(long the thread ID of a thread id) Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the thread with the specified ID. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded.
public long[]	Returns: an array of long values, each of which is an approximation of the total memory allocated, in bytes, in heap memory for the thread whose ID is in the corresponding element of the input array of IDs. getThreadAllocatedBytes(long[] an array of thread IDs. ids) Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for each thread whose ID is in the input array `ids`.
public long[]	Returns: an array of long values, each of which is the amount of CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; `-1` otherwise. getThreadCpuTime(long[] an array of thread IDs. ids) Returns the total CPU time for each thread whose ID is in the input array `ids` in nanoseconds.
public long[]	Returns: an array of long values, each of which is the amount of user mode CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; `-1` otherwise. getThreadUserTime(long[] an array of thread IDs. ids) Returns the CPU time that each thread whose ID is in the input array `ids` has executed in user mode in nanoseconds.
public default long	Returns: an approximation of the total memory allocated, in bytes, in heap memory since the Java virtual machine was started, if thread memory allocation measurement is enabled; `-1` otherwise. getTotalThreadAllocatedBytes() Returns an approximation of the total amount of memory, in bytes, allocated in heap memory by all threads since the Java virtual machine started.
public boolean	Returns: `true` if thread memory allocation measurement is enabled; `false` otherwise. isThreadAllocatedMemoryEnabled() Tests if thread memory allocation measurement is enabled.
public boolean	Returns: `true` if the Java virtual machine implementation supports thread memory allocation measurement; `false` otherwise. isThreadAllocatedMemorySupported() Tests if the Java virtual machine implementation supports thread memory allocation measurement.
public void	setThreadAllocatedMemoryEnabled(boolean `true` to enable; `false` to disable. enable) Enables or disables thread memory allocation measurement.

Method Detail

getCurrentThreadAllocatedBytes back to summary

getCurrentThreadAllocatedBytes	back to summary
public default long getCurrentThreadAllocatedBytes() Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the current thread. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded. This is a convenience method for local management use and is equivalent to calling: `getThreadAllocatedBytes`(Thread.currentThread().threadId()); Returns:long an approximation of the total memory allocated, in bytes, in heap memory for the current thread if thread memory allocation measurement is enabled; `-1` otherwise. Exceptions UnsupportedOperationException: if the Java virtual machine implementation does not support thread memory allocation measurement. Since 14 See Also `isThreadAllocatedMemorySupported`, `isThreadAllocatedMemoryEnabled`, `setThreadAllocatedMemoryEnabled`

public default long getCurrentThreadAllocatedBytes()

Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the current thread. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded.

This is a convenience method for local management use and is equivalent to calling:

  getThreadAllocatedBytes(Thread.currentThread().threadId());

Returns:long

an approximation of the total memory allocated, in bytes, in heap memory for the current thread if thread memory allocation measurement is enabled; -1 otherwise.

Exceptions

UnsupportedOperationException:: if the Java virtual machine implementation does not support thread memory allocation measurement.

Since

getThreadAllocatedBytes back to summary

getThreadAllocatedBytes	back to summary
public long getThreadAllocatedBytes(long id) Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the thread with the specified ID. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded. If the thread with the specified ID is a virtual thread, is not alive, or does not exist, this method returns `-1`. If thread memory allocation measurement is disabled, this method returns `-1`. A thread is alive if it has been started and has not yet terminated. If thread memory allocation 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 thread memory allocation measurement starts. Parameters id:long the thread ID of a thread Returns:long an approximation of the total memory allocated, in bytes, in heap memory for the thread with the specified ID if the thread with the specified ID is a platform thread, the thread is alive, and thread memory allocation measurement is enabled; `-1` otherwise. Exceptions IllegalArgumentException: if `id` `<=` `0`. UnsupportedOperationException: if the Java virtual machine implementation does not support thread memory allocation measurement. See Also `isThreadAllocatedMemorySupported`, `isThreadAllocatedMemoryEnabled`, `setThreadAllocatedMemoryEnabled`

public long getThreadAllocatedBytes(long id)

Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for the thread with the specified ID. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded.

If the thread with the specified ID is a virtual thread, is not alive, or does not exist, this method returns -1. If thread memory allocation measurement is disabled, this method returns -1. A thread is alive if it has been started and has not yet terminated.

If thread memory allocation 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 thread memory allocation measurement starts.

Parameters

id:long: the thread ID of a thread

Returns:long

an approximation of the total memory allocated, in bytes, in heap memory for the thread with the specified ID if the thread with the specified ID is a platform thread, the thread is alive, and thread memory allocation measurement is enabled; -1 otherwise.

Exceptions

IllegalArgumentException:: if id <= 0.
UnsupportedOperationException:: if the Java virtual machine implementation does not support thread memory allocation measurement.

getThreadAllocatedBytes back to summary

getThreadAllocatedBytes	back to summary
public long[] getThreadAllocatedBytes(long[] ids) Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for each thread whose ID is in the input array `ids`. The returned values are approximations because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded. This method is equivalent to calling the `getThreadAllocatedBytes(long)` method for each thread ID in the input array `ids` and setting the returned value in the corresponding element of the returned array. Parameters ids:long[] an array of thread IDs. Returns:long[] an array of long values, each of which is an approximation of the total memory allocated, in bytes, in heap memory for the thread whose ID is in the corresponding element of the input array of IDs. Exceptions NullPointerException: if `ids` is `null` IllegalArgumentException: if any element in the input array `ids` is `<=` `0`. UnsupportedOperationException: if the Java virtual machine implementation does not support thread memory allocation measurement. See Also `getThreadAllocatedBytes(long)`, `isThreadAllocatedMemorySupported`, `isThreadAllocatedMemoryEnabled`, `setThreadAllocatedMemoryEnabled`

public long[] getThreadAllocatedBytes(long[] ids)

Returns an approximation of the total amount of memory, in bytes, allocated in heap memory for each thread whose ID is in the input array ids. The returned values are approximations because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded.

This method is equivalent to calling the getThreadAllocatedBytes(long) method for each thread ID in the input array ids and setting the returned value in the corresponding element of the returned array.

Parameters

ids:long[]: an array of thread IDs.

Returns:long[]

an array of long values, each of which is an approximation of the total memory allocated, in bytes, in heap memory for the thread whose ID is in the corresponding element of the input array of IDs.

Exceptions

NullPointerException:: if ids is null
IllegalArgumentException:: if any element in the input array ids is <= 0.
UnsupportedOperationException:: if the Java virtual machine implementation does not support thread memory allocation measurement.

getThreadCpuTime back to summary

getThreadCpuTime	back to summary
public long[] getThreadCpuTime(long[] ids) Returns the total CPU time for each thread whose ID is in the input array `ids` in nanoseconds. The returned values are of nanoseconds precision but not necessarily nanoseconds accuracy. This method is equivalent to calling the `ThreadMXBean#getThreadCpuTime(long)` method for each thread ID in the input array `ids` and setting the returned value in the corresponding element of the returned array. Parameters ids:long[] an array of thread IDs. Returns:long[] an array of long values, each of which is the amount of CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; `-1` otherwise. Exceptions NullPointerException: if `ids` is `null` IllegalArgumentException: if any element in the input array `ids` is `<=` `0`. UnsupportedOperationException: if the Java virtual machine implementation does not support CPU time measurement. See Also `ThreadMXBean#getThreadCpuTime(long)`, `getThreadUserTime`, `ThreadMXBean#isThreadCpuTimeSupported`, `ThreadMXBean#isThreadCpuTimeEnabled`, `ThreadMXBean#setThreadCpuTimeEnabled`

public long[] getThreadCpuTime(long[] ids)

Returns the total CPU time for each thread whose ID is in the input array ids in nanoseconds. The returned values are of nanoseconds precision but not necessarily nanoseconds accuracy.

This method is equivalent to calling the ThreadMXBean#getThreadCpuTime(long) method for each thread ID in the input array ids and setting the returned value in the corresponding element of the returned array.

Parameters

ids:long[]: an array of thread IDs.

Returns:long[]

an array of long values, each of which is the amount of CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; -1 otherwise.

Exceptions

NullPointerException:: if ids is null
IllegalArgumentException:: if any element in the input array ids is <= 0.
UnsupportedOperationException:: if the Java virtual machine implementation does not support CPU time measurement.

getThreadUserTime back to summary

getThreadUserTime	back to summary
public long[] getThreadUserTime(long[] ids) Returns the CPU time that each thread whose ID is in the input array `ids` has executed in user mode in nanoseconds. The returned values are of nanoseconds precision but not necessarily nanoseconds accuracy. This method is equivalent to calling the `ThreadMXBean#getThreadUserTime(long)` method for each thread ID in the input array `ids` and setting the returned value in the corresponding element of the returned array. Parameters ids:long[] an array of thread IDs. Returns:long[] an array of long values, each of which is the amount of user mode CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; `-1` otherwise. Exceptions NullPointerException: if `ids` is `null` IllegalArgumentException: if any element in the input array `ids` is `<=` `0`. UnsupportedOperationException: if the Java virtual machine implementation does not support CPU time measurement. See Also `ThreadMXBean#getThreadUserTime(long)`, `getThreadCpuTime`, `ThreadMXBean#isThreadCpuTimeSupported`, `ThreadMXBean#isThreadCpuTimeEnabled`, `ThreadMXBean#setThreadCpuTimeEnabled`

public long[] getThreadUserTime(long[] ids)

Returns the CPU time that each thread whose ID is in the input array ids has executed in user mode in nanoseconds. The returned values are of nanoseconds precision but not necessarily nanoseconds accuracy.

This method is equivalent to calling the ThreadMXBean#getThreadUserTime(long) method for each thread ID in the input array ids and setting the returned value in the corresponding element of the returned array.

Parameters

ids:long[]: an array of thread IDs.

Returns:long[]

an array of long values, each of which is the amount of user mode CPU time the thread whose ID is in the corresponding element of the input array of IDs has used, if the thread of a specified ID is a platform thread, the thread is alive, and CPU time measurement is enabled; -1 otherwise.

Exceptions

NullPointerException:: if ids is null
IllegalArgumentException:: if any element in the input array ids is <= 0.
UnsupportedOperationException:: if the Java virtual machine implementation does not support CPU time measurement.

getTotalThreadAllocatedBytes back to summary

getTotalThreadAllocatedBytes	back to summary
public default long getTotalThreadAllocatedBytes() Returns an approximation of the total amount of memory, in bytes, allocated in heap memory by all threads since the Java virtual machine started. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded. Implementation Specification The default implementation throws `UnsupportedOperationException` if the Java virtual machine implementation does not support thread memory allocation measurement, and otherwise acts as though thread memory allocation measurement is disabled. Returns:long an approximation of the total memory allocated, in bytes, in heap memory since the Java virtual machine was started, if thread memory allocation measurement is enabled; `-1` otherwise. Exceptions UnsupportedOperationException: if the Java virtual machine implementation does not support thread memory allocation measurement. Since 21 See Also `isThreadAllocatedMemorySupported`, `isThreadAllocatedMemoryEnabled`, `setThreadAllocatedMemoryEnabled`

public default long getTotalThreadAllocatedBytes()

Returns an approximation of the total amount of memory, in bytes, allocated in heap memory by all threads since the Java virtual machine started. The returned value is an approximation because some Java virtual machine implementations may use object allocation mechanisms that result in a delay between the time an object is allocated and the time its size is recorded.

Implementation Specification

The default implementation throws UnsupportedOperationException if the Java virtual machine implementation does not support thread memory allocation measurement, and otherwise acts as though thread memory allocation measurement is disabled.

Returns:long

an approximation of the total memory allocated, in bytes, in heap memory since the Java virtual machine was started, if thread memory allocation measurement is enabled; -1 otherwise.

Exceptions

UnsupportedOperationException:: if the Java virtual machine implementation does not support thread memory allocation measurement.

Since

isThreadAllocatedMemoryEnabled back to summary

isThreadAllocatedMemoryEnabled	back to summary
public boolean isThreadAllocatedMemoryEnabled() Tests if thread memory allocation measurement is enabled. Returns:boolean `true` if thread memory allocation measurement is enabled; `false` otherwise. Exceptions UnsupportedOperationException: if the Java virtual machine does not support thread memory allocation measurement. See Also `isThreadAllocatedMemorySupported`

public boolean isThreadAllocatedMemoryEnabled()

Tests if thread memory allocation measurement is enabled.

Returns:boolean

true if thread memory allocation measurement is enabled; false otherwise.

Exceptions

UnsupportedOperationException:: if the Java virtual machine does not support thread memory allocation measurement.

See Also

isThreadAllocatedMemorySupported

isThreadAllocatedMemorySupported back to summary

isThreadAllocatedMemorySupported	back to summary
public boolean isThreadAllocatedMemorySupported() Tests if the Java virtual machine implementation supports thread memory allocation measurement. Returns:boolean `true` if the Java virtual machine implementation supports thread memory allocation measurement; `false` otherwise.

public boolean isThreadAllocatedMemorySupported()

Tests if the Java virtual machine implementation supports thread memory allocation measurement.

Returns:boolean: true if the Java virtual machine implementation supports thread memory allocation measurement; false otherwise.

setThreadAllocatedMemoryEnabled back to summary

setThreadAllocatedMemoryEnabled	back to summary
public void setThreadAllocatedMemoryEnabled(boolean enable) Enables or disables thread memory allocation measurement. The default is platform dependent. Parameters enable:boolean `true` to enable; `false` to disable. Exceptions UnsupportedOperationException: if the Java virtual machine does not support thread memory allocation measurement. See Also `isThreadAllocatedMemorySupported`

public void setThreadAllocatedMemoryEnabled(boolean enable)

Enables or disables thread memory allocation measurement. The default is platform dependent.

Parameters

enable:boolean: true to enable; false to disable.

Exceptions

UnsupportedOperationException:: if the Java virtual machine does not support thread memory allocation measurement.

See Also

isThreadAllocatedMemorySupported

public Interface ThreadMXBean

Method Summary

Method Detail