All Superinterfaces:

MemoryMXBean, PlatformManagedObject

All Known Implementing Classes:

ExtendedMemoryMXBeanImpl
```
public interface MemoryMXBean
extends MemoryMXBean
```
The OpenJ9 extension interface for monitoring the virtual machine's memory management system.

Since:

1.5

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method	Description
`int`	`getCurrentGCThreads()`	Returns the number of GC worker threads that participated in the most recent collection.
`long`	`getGCMainThreadCpuUsed()`	Returns the amount of CPU time spent in the GC by the main thread, in milliseconds.
`long`	`getGCMasterThreadCpuUsed()`	Deprecated, for removal: This API element is subject to removal in a future version. renamed to getGCMainThreadCpuUsed
`String`	`getGCMode()`	Returns the current GC mode as a human-readable string.
`long`	`getGCSlaveThreadsCpuUsed()`	Deprecated, for removal: This API element is subject to removal in a future version. renamed to getGCWorkerThreadsCpuUsed
`long`	`getGCWorkerThreadsCpuUsed()`	Returns the total amount of CPU time spent in the GC by all worker threads, in milliseconds.
`long`	`getMaxHeapSize()`	Get the current maximum heap size in bytes.
`long`	`getMaxHeapSizeLimit()`	Get the maximum size in bytes to which the max heap size could be increased in the currently running VM.
`int`	`getMaximumGCThreads()`	Returns the maximum number of GC worker threads.
`long`	`getMinHeapSize()`	Get the minimum heap size in bytes.
`long`	`getSharedClassCacheFreeSpace()`	Returns the free space in bytes of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheMaxAotBytes()`	Returns the maximum space allowed for AOT data of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheMaxAotUnstoredBytes()`	Returns the bytes which are not stored into the shared classes cache due to the current setting of maximum space allowed for AOT data.
`long`	`getSharedClassCacheMaxJitDataBytes()`	Returns the maximum space allowed for JIT data of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheMaxJitDataUnstoredBytes()`	Returns the bytes which are not stored into the shared classes cache due to the current setting of maximum space allowed for JIT data.
`long`	`getSharedClassCacheMinAotBytes()`	Returns the minimum space reserved for AOT data of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheMinJitDataBytes()`	Returns the minimum space reserved for JIT data of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheSize()`	Returns the total size in bytes of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheSoftmxBytes()`	Returns the softmx size in bytes of the cache that the JVM is currently connected to.
`long`	`getSharedClassCacheSoftmxUnstoredBytes()`	Returns the bytes which are not stored into the shared classes cache due to the current setting of softmx in shared classes.
`boolean`	`isSetMaxHeapSizeSupported()`	Query whether the VM supports runtime reconfiguration of the maximum heap size through the setMaxHeapSize() call.
`void`	`setMaxHeapSize(long size)`	Set the current maximum heap size to `size`.
`boolean`	`setSharedClassCacheMaxAotBytes(long value)`	Set the maximum shared classes cache space allowed for AOT data to `value` bytes.
`boolean`	`setSharedClassCacheMaxJitDataBytes(long value)`	Set the maximum shared classes cache space allowed for JIT data to `value` bytes.
`boolean`	`setSharedClassCacheMinAotBytes(long value)`	Set the minimum shared classes cache space reserved for AOT data to `value` bytes.
`boolean`	`setSharedClassCacheMinJitDataBytes(long value)`	Set the minimum shared classes cache space reserved for JIT data to `value` bytes.
`boolean`	`setSharedClassCacheSoftmxBytes(long value)`	Set the shared class softmx size to `value`.

Methods declared in interface java.lang.management.MemoryMXBean
gc, getHeapMemoryUsage, getNonHeapMemoryUsage, getObjectPendingFinalizationCount, isVerbose, setVerbose

Methods declared in interface java.lang.management.PlatformManagedObject
getObjectName

- Method Detail
  - getMaxHeapSizeLimit
```
long getMaxHeapSizeLimit()
```
    Get the maximum size in bytes to which the max heap size could be increased in the currently running VM. This may be larger than the current max heap size.
    
    Returns:
    
    value of -Xmx in bytes
  - getMaxHeapSize
```
long getMaxHeapSize()
```
    Get the current maximum heap size in bytes.
    
    Returns:
    
    current value of -Xsoftmx in bytes
  - getMinHeapSize
```
long getMinHeapSize()
```
    Get the minimum heap size in bytes.
    
    Returns:
    
    value of -Xms in bytes
  - setMaxHeapSize
```
void setMaxHeapSize(long size)
```
    Set the current maximum heap size to size. The parameter specifies the max heap size in bytes and must be between getMinHeapSize() and getMaxHeapSizeLimit(). See -Xsoftmx in the command line reference for additional details on the effect of setting softmx.
    
    Parameters:
    
    size - new -Xsoftmx value in bytes
    
    Throws:
    
    UnsupportedOperationException - if this operation is not supported.
    
    IllegalArgumentException - if input value size is either less than getMinHeapSize() or greater than getMaxHeapSizeLimit().
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - isSetMaxHeapSizeSupported
```
boolean isSetMaxHeapSizeSupported()
```
    Query whether the VM supports runtime reconfiguration of the maximum heap size through the setMaxHeapSize() call.
    
    Returns:
    
    true if setMaxHeapSize is supported, false otherwise
  - getSharedClassCacheSize
```
long getSharedClassCacheSize()
```
    Returns the total size in bytes of the cache that the JVM is currently connected to.
    
    Returns:
    
    the number of bytes in the shared class cache.
  - getSharedClassCacheSoftmxBytes
```
long getSharedClassCacheSoftmxBytes()
```
    Returns the softmx size in bytes of the cache that the JVM is currently connected to.
    
    Returns:
    
    the softmx bytes in the shared class cache or cache size if it is not set.
  - getSharedClassCacheMinAotBytes
```
long getSharedClassCacheMinAotBytes()
```
    Returns the minimum space reserved for AOT data of the cache that the JVM is currently connected to.
    
    Returns:
    
    the minimum shared classes cache space reserved for AOT data in bytes or -1 if it is not set.
  - getSharedClassCacheMaxAotBytes
```
long getSharedClassCacheMaxAotBytes()
```
    Returns the maximum space allowed for AOT data of the cache that the JVM is currently connected to.
    
    Returns:
    
    the maximum shared classes cache space allowed for AOT data or -1 if it is not set.
  - getSharedClassCacheMinJitDataBytes
```
long getSharedClassCacheMinJitDataBytes()
```
    Returns the minimum space reserved for JIT data of the cache that the JVM is currently connected to.
    
    Returns:
    
    the minimum shared classes cache space reserved for JIT data or -1 if it is not set.
  - getSharedClassCacheMaxJitDataBytes
```
long getSharedClassCacheMaxJitDataBytes()
```
    Returns the maximum space allowed for JIT data of the cache that the JVM is currently connected to.
    
    Returns:
    
    the maximum shared classes cache space allowed for JIT data or -1 if it is not set.
  - setSharedClassCacheSoftmxBytes
```
boolean setSharedClassCacheSoftmxBytes(long value)
```
    Set the shared class softmx size to value. The parameter specifies the softmx in bytes. See -Xscmx in the command line reference for additional details on the effect of setting shared class softmx.
    
    Parameters:
    
    value - new shared cache soft max value in bytes
    
    Returns:
    
    whether the requested operation has been completed.
    
    Throws:
    
    IllegalArgumentException - if input value value is less than 0.
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - setSharedClassCacheMinAotBytes
```
boolean setSharedClassCacheMinAotBytes(long value)
```
    Set the minimum shared classes cache space reserved for AOT data to value bytes. See -Xscminaot in the command line reference for additional details on the effect of setting shared class -Xscminaot.
    
    Parameters:
    
    value - new -Xscminaot value in bytes
    
    Returns:
    
    whether the requested operation has been completed.
    
    Throws:
    
    IllegalArgumentException - if input value value is less than 0.
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - setSharedClassCacheMaxAotBytes
```
boolean setSharedClassCacheMaxAotBytes(long value)
```
    Set the maximum shared classes cache space allowed for AOT data to value bytes. See -Xscmaxaot in the command line reference for additional details on the effect of setting shared class -Xscmaxaot.
    
    Parameters:
    
    value - new -Xscmaxaot value in bytes
    
    Returns:
    
    whether the requested operation has been completed.
    
    Throws:
    
    IllegalArgumentException - if input value value is less than 0.
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - setSharedClassCacheMinJitDataBytes
```
boolean setSharedClassCacheMinJitDataBytes(long value)
```
    Set the minimum shared classes cache space reserved for JIT data to value bytes. See -Xscminjitdata in the command line reference for additional details on the effect of setting shared class -Xscminjitdata.
    
    Parameters:
    
    value - new -Xscminjitdata value in bytes
    
    Returns:
    
    whether the requested operation has been completed.
    
    Throws:
    
    IllegalArgumentException - if input value value is less than 0.
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - setSharedClassCacheMaxJitDataBytes
```
boolean setSharedClassCacheMaxJitDataBytes(long value)
```
    Set the maximum shared classes cache space allowed for JIT data to value bytes. See -Xscmaxjitdata in the command line reference for additional details on the effect of setting shared class -Xscmaxjitdata.
    
    Parameters:
    
    value - new -Xscmaxjitdata value in bytes
    
    Returns:
    
    whether the requested operation has been completed.
    
    Throws:
    
    IllegalArgumentException - if input value value is less than 0.
    
    SecurityException - if a SecurityManager is being used and the caller does not have the ManagementPermission value of "control".
  - getSharedClassCacheSoftmxUnstoredBytes
```
long getSharedClassCacheSoftmxUnstoredBytes()
```
    Returns the bytes which are not stored into the shared classes cache due to the current setting of softmx in shared classes.
    
    Returns:
    
    the unstored bytes.
  - getSharedClassCacheMaxAotUnstoredBytes
```
long getSharedClassCacheMaxAotUnstoredBytes()
```
    Returns the bytes which are not stored into the shared classes cache due to the current setting of maximum space allowed for AOT data.
    
    Returns:
    
    the unstored bytes.
  - getSharedClassCacheMaxJitDataUnstoredBytes
```
long getSharedClassCacheMaxJitDataUnstoredBytes()
```
    Returns the bytes which are not stored into the shared classes cache due to the current setting of maximum space allowed for JIT data.
    
    Returns:
    
    the unstored bytes.
  - getSharedClassCacheFreeSpace
```
long getSharedClassCacheFreeSpace()
```
    Returns the free space in bytes of the cache that the JVM is currently connected to.
    
    Returns:
    
    the number of bytes free in the shared class cache.
  - getGCMode
```
String getGCMode()
```
    Returns the current GC mode as a human-readable string.
    
    Returns:
    
    a String describing the mode the GC is currently operating in
  - getGCMasterThreadCpuUsed
```
@Deprecated(forRemoval=true,
            since="15")
long getGCMasterThreadCpuUsed()
```
    Deprecated, for removal: This API element is subject to removal in a future version.
    renamed to getGCMainThreadCpuUsed
    
    Returns the amount of CPU time spent in the GC by the master thread, in milliseconds.
    
    Returns:
    
    CPU time used in milliseconds
  - getGCMainThreadCpuUsed
```
long getGCMainThreadCpuUsed()
```
    Returns the amount of CPU time spent in the GC by the main thread, in milliseconds.
    
    Returns:
    
    CPU time used in milliseconds
  - getGCSlaveThreadsCpuUsed
```
@Deprecated(forRemoval=true,
            since="15")
long getGCSlaveThreadsCpuUsed()
```
    Deprecated, for removal: This API element is subject to removal in a future version.
    renamed to getGCWorkerThreadsCpuUsed
    
    Returns the total amount of CPU time spent in the GC by all slave threads, in milliseconds.
    
    Returns:
    
    CPU time used in milliseconds
  - getGCWorkerThreadsCpuUsed
```
long getGCWorkerThreadsCpuUsed()
```
    Returns the total amount of CPU time spent in the GC by all worker threads, in milliseconds.
    
    Returns:
    
    CPU time used in milliseconds
  - getMaximumGCThreads
```
int getMaximumGCThreads()
```
    Returns the maximum number of GC worker threads.
    
    Returns:
    
    maximum number of GC worker threads
  - getCurrentGCThreads
```
int getCurrentGCThreads()
```
    Returns the number of GC worker threads that participated in the most recent collection.
    
    Returns:
    
    number of active GC worker threads

Interface MemoryMXBean

Method Summary

Methods declared in interface java.lang.management.MemoryMXBean

Methods declared in interface java.lang.management.PlatformManagedObject

Method Detail

getMaxHeapSizeLimit

getMaxHeapSize

getMinHeapSize

setMaxHeapSize

isSetMaxHeapSizeSupported

getSharedClassCacheSize

getSharedClassCacheSoftmxBytes

getSharedClassCacheMinAotBytes

getSharedClassCacheMaxAotBytes

getSharedClassCacheMinJitDataBytes

getSharedClassCacheMaxJitDataBytes

setSharedClassCacheSoftmxBytes

setSharedClassCacheMinAotBytes

setSharedClassCacheMaxAotBytes

setSharedClassCacheMinJitDataBytes

setSharedClassCacheMaxJitDataBytes

getSharedClassCacheSoftmxUnstoredBytes

getSharedClassCacheMaxAotUnstoredBytes

getSharedClassCacheMaxJitDataUnstoredBytes

getSharedClassCacheFreeSpace

getGCMode

getGCMasterThreadCpuUsed

getGCMainThreadCpuUsed

getGCSlaveThreadsCpuUsed

getGCWorkerThreadsCpuUsed

getMaximumGCThreads

getCurrentGCThreads