001 /* GarbageCollectorMXBean.java - Interface for a garbage collector bean 002 Copyright (C) 2006 Free Software Foundation 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 package java.lang.management; 039 040 /** 041 * Provides access to information about the garbage collectors 042 * of the virtual machine. Garbage collectors are responsible 043 * for removing unreferenced objects from memory. A garbage 044 * collector is a type of memory manager, so this interface 045 * is combined with that of generic memory managers. An instance 046 * of this bean for each garbage collector is obtained by calling 047 * {@link ManagementFactory#getGarbageCollectorMXBeans()}. 048 * 049 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 050 * @since 1.5 051 */ 052 public interface GarbageCollectorMXBean 053 extends MemoryManagerMXBean 054 { 055 056 /** 057 * Returns the number of collections the garbage collector 058 * represented by this bean has made. -1 is returned if the 059 * collection count is undefined. 060 * 061 * @return the number of collections made, or -1 if this is 062 * undefined. 063 */ 064 long getCollectionCount(); 065 066 /** 067 * Returns the accumulated number of milliseconds this garbage 068 * collector has spent freeing the memory used by unreferenced 069 * objects. -1 is returned if the collection time is undefined. 070 * Note that the accumulated time may not change, even when the 071 * collection count increases, if the time taken is sufficiently 072 * short; this depends on the resolution of the timer used. 073 * 074 * @return the accumulated number of milliseconds spent collecting, 075 * or -1 if this is undefined. 076 */ 077 long getCollectionTime(); 078 079 }