Module jdk.management
Package com.sun.management

Class GcInfo

java.lang.Object
com.sun.management.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
Since:
9

  • Method Details

    • getId

      public long getId()
      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:
      CompositeData 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
      Parameters:
      cd - CompositeData representing a GcInfo
      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.

    • containsKey

      public boolean containsKey(String key)
      Returns true if and only if this CompositeData instance contains an item whose name is key. If key is a null or empty String, this method simply returns false.
      Specified by:
      containsKey in interface CompositeData
      Parameters:
      key - the key to be tested.
      Returns:
      true if this CompositeData contains the key.

    • containsValue

      public boolean containsValue(Object value)
      Returns true if and only if this CompositeData instance contains an item whose value is value.
      Specified by:
      containsValue in interface CompositeData
      Parameters:
      value - the value to be tested.
      Returns:
      true if this CompositeData contains the value.

    • equals

      public boolean equals(Object obj)
      Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison. The implementation in Object answers true only if the argument is the exact same object as the receiver (==).
      Specified by:
      equals in interface CompositeData
      Overrides:
      equals in class Object
      Parameters:
      obj - Object the object to compare with this object.
      Returns:
      boolean true if the object is the same as this object false if it is different from this object.
      See Also:

    • get

      public Object get(String key)
      Returns the value of the item whose name is key.
      Specified by:
      get in interface CompositeData
      Parameters:
      key - the name of the item.
      Returns:
      the value associated with this key.

    • getAll

      public Object[] getAll(String[] keys)
      Returns an array of the values of the items whose names are specified by keys, in the same order as keys.
      Specified by:
      getAll in interface CompositeData
      Parameters:
      keys - the names of the items.
      Returns:
      the values corresponding to the keys.

    • getCompositeType

      public CompositeType getCompositeType()
      Returns the composite type of this composite data instance.
      Specified by:
      getCompositeType in interface CompositeData
      Returns:
      the type of this CompositeData.

    • hashCode

      public int hashCode()
      Answers an integer hash code for the receiver. Any two objects which answer true when passed to .equals must answer the same value for this method.
      Specified by:
      hashCode in interface CompositeData
      Overrides:
      hashCode in class Object
      Returns:
      the receiver's hash.
      See Also:

    • toString

      public String toString()
      Answers a string containing a concise, human-readable description of the receiver.
      Specified by:
      toString in interface CompositeData
      Overrides:
      toString in class Object
      Returns:
      String a printable representation for the receiver.

    • values

      public Collection<?> values()
      Returns an unmodifiable Collection view of the item values contained in this CompositeData instance. The returned collection's iterator will return the values in the ascending lexicographic order of the corresponding item names.
      Specified by:
      values in interface CompositeData
      Returns:
      the values.

    • 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.