Class GcInfo

All Implemented Interfaces:
CompositeData, CompositeDataView 
public class GcInfo
extends Object
implements CompositeData, CompositeDataView

Garbage collection information. It contains the following information for one garbage collection as well as GC-specific attributes:

  • Start time
  • End time
  • Duration
  • Memory usage before the collection starts
  • Memory usage after the collection ends

GcInfo is a CompositeData The GC-specific attributes can be obtained via the CompositeData interface. This is a historical relic, and other classes should not copy this pattern. Use CompositeDataView instead.

MXBean Mapping

GcInfo is mapped to a CompositeData with attributes as specified in the from method.
Since:
1.5

Methods

Modifier and Type Method Description
static GcInfo from​(CompositeData cd)

Returns a GcInfo object represented by the given CompositeData.
long getDuration()

Returns the elapsed time of this GC in milliseconds.
long getEndTime()

Returns the end time of this GC in milliseconds since the Java virtual machine was started.
long getId()

Returns the identifier of this garbage collection which is the number of collections that this collector has done.
Map<String,​MemoryUsage> getMemoryUsageAfterGc()

Returns the memory usage of all memory pools at the end of this GC.
Map<String,​MemoryUsage> getMemoryUsageBeforeGc()

Returns the memory usage of all memory pools at the beginning of this GC.
long getStartTime()

Returns the start time of this GC in milliseconds since the Java virtual machine was started.
CompositeData toCompositeData​(CompositeType ct)

Return the CompositeData representation of this GcInfo, including any GC-specific attributes.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods declared in interface javax.management.openmbean.CompositeData

containsKey, containsValue, equals, get, getAll, getCompositeType, hashCode, toString, values

Methods

getId

public long getId()

Returns the identifier of this garbage collection which is the number of collections that this collector has done.

Returns:
the identifier of this garbage collection which is the number of collections that this collector has done.

getStartTime

public long getStartTime()

Returns the start time of this GC in milliseconds since the Java virtual machine was started.

Returns:
the start time of this GC.

getEndTime

public long getEndTime()

Returns the end time of this GC in milliseconds since the Java virtual machine was started.

Returns:
the end time of this GC.

getDuration

public long getDuration()

Returns the elapsed time of this GC in milliseconds.

Returns:
the elapsed time of this GC in milliseconds.

getMemoryUsageBeforeGc

public Map<String,MemoryUsage> getMemoryUsageBeforeGc()

Returns the memory usage of all memory pools at the beginning of this GC. This method returns a Map of the name of a memory pool to the memory usage of the corresponding memory pool before GC starts.

Returns:
a Map of memory pool names to the memory usage of a memory pool before GC starts.

getMemoryUsageAfterGc

public Map<String,MemoryUsage> getMemoryUsageAfterGc()

Returns the memory usage of all memory pools at the end of this GC. This method returns a Map of the name of a memory pool to the memory usage of the corresponding memory pool when GC finishes.

Returns:
a Map of memory pool names to the memory usage of a memory pool when GC finishes.

from

public static GcInfo from(CompositeData cd)

Returns a GcInfo object represented by the given CompositeData. The given CompositeData must contain all the following attributes:

Attribute Name Type
index java.lang.Long
startTime java.lang.Long
endTime java.lang.Long
memoryUsageBeforeGc javax.management.openmbean.TabularData
memoryUsageAfterGc javax.management.openmbean.TabularData

Returns:
a GcInfo object represented by cd if cd is not null; null otherwise.
Throws:
IllegalArgumentException - if cd does not represent a GcInfo object with the attributes described above.

toCompositeData

public CompositeData toCompositeData(CompositeType ct)

Return the CompositeData representation of this GcInfo, including any GC-specific attributes. The returned value will have at least all the attributes described in the from method, plus optionally other attributes.

Specified by:
toCompositeData in interface CompositeDataView
Parameters:
ct - the CompositeType that the caller expects. This parameter is ignored and can be null.
Returns:
the CompositeData representation.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/11/docs/api/jdk.management/com/sun/management/GcInfo.html