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package java.lang.management;
The management interface for the garbage collection of the Java virtual machine. Garbage collection is the process that the Java virtual machine uses to find and reclaim unreachable objects to free up memory space. A garbage collector is one type of memory manager. A Java virtual machine may have one or more instances of
the implementation class of this interface.
An instance implementing this interface is
an MXBean that can be obtained by calling the ManagementFactory.getGarbageCollectorMXBeans method or from the
platform MBeanServer method.
The ObjectName for uniquely identifying the MXBean for a garbage collector within an MBeanServer is:
java.lang:type=GarbageCollector,name=collector's name
It can be obtained by calling the PlatformManagedObject.getObjectName method. A platform usually includes additional platform-dependent information specific to a garbage collection algorithm for monitoring. Author: Mandy Chung See Also: Since: 1.5
/**
* The management interface for the garbage collection of
* the Java virtual machine. Garbage collection is the process
* that the Java virtual machine uses to find and reclaim unreachable
* objects to free up memory space. A garbage collector is one type of
* {@link MemoryManagerMXBean memory manager}.
*
* <p> A Java virtual machine may have one or more instances of
* the implementation class of this interface.
* An instance implementing this interface is
* an <a href="ManagementFactory.html#MXBean">MXBean</a>
* that can be obtained by calling
* the {@link ManagementFactory#getGarbageCollectorMXBeans} method or
* from the {@link ManagementFactory#getPlatformMBeanServer
* platform MBeanServer} method.
*
* <p>The {@code ObjectName} for uniquely identifying the MXBean for
* a garbage collector within an MBeanServer is:
* <blockquote>
* {@link ManagementFactory#GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE
* java.lang:type=GarbageCollector}{@code ,name=}<i>collector's name</i>
* </blockquote>
*
* It can be obtained by calling the
* {@link PlatformManagedObject#getObjectName} method.
*
* A platform usually includes additional platform-dependent information
* specific to a garbage collection algorithm for monitoring.
*
* @see ManagementFactory#getPlatformMXBeans(Class)
* @see MemoryMXBean
*
* @see <a href="../../../javax/management/package-summary.html">
* JMX Specification.</a>
* @see <a href="package-summary.html#examples">
* Ways to Access MXBeans</a>
*
* @author Mandy Chung
* @since 1.5
*/
public interface GarbageCollectorMXBean extends MemoryManagerMXBean {
Returns the total number of collections that have occurred. This method returns -1 if the collection count is undefined for this collector. Returns: the total number of collections that have occurred.
/**
* Returns the total number of collections that have occurred.
* This method returns {@code -1} if the collection count is undefined for
* this collector.
*
* @return the total number of collections that have occurred.
*/
public long getCollectionCount();
Returns the approximate accumulated collection elapsed time in milliseconds. This method returns -1 if the collection elapsed time is undefined for this collector.
The Java virtual machine implementation may use a high resolution
timer to measure the elapsed time. This method may return the
same value even if the collection count has been incremented
if the collection elapsed time is very short.
Returns: the approximate accumulated collection elapsed time
in milliseconds.
/**
* Returns the approximate accumulated collection elapsed time
* in milliseconds. This method returns {@code -1} if the collection
* elapsed time is undefined for this collector.
* <p>
* The Java virtual machine implementation may use a high resolution
* timer to measure the elapsed time. This method may return the
* same value even if the collection count has been incremented
* if the collection elapsed time is very short.
*
* @return the approximate accumulated collection elapsed time
* in milliseconds.
*/
public long getCollectionTime();
}