java - JDK 类中 java.lang.ref.WeakReference 对象的内存泄漏

Question

下面的简单代码再现了java.lang.ref.WeakReference对象在堆中的增长:

public static void main(String[] args) throws Exception {

while (true) {
java.util.logging.Logger.getAnonymousLogger();
Thread.sleep(1);
}
}

这是 jmap 命令在几秒内的输出:

user@t1007:~> jmap -d64 -histo:live 29201|grep WeakReference
8: 22493 1079664 java.lang.ref.WeakReference
31: 1 32144 [Ljava.lang.ref.WeakReference;
106: 17 952

com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference
user@t1007:~> jmap -d64 -histo:live 29201|grep WeakReference
8: 23191 1113168 java.lang.ref.WeakReference
31: 1 32144 [Ljava.lang.ref.WeakReference;
103: 17 952

com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference
user@t1007:~> jmap -d64 -histo:live 29201|grep WeakReference
8: 23804 1142592 java.lang.ref.WeakReference
31: 1 32144 [Ljava.lang.ref.WeakReference;
103: 17 952 com.sun.jmx.mbeanserver.WeakIdentityHashMap$IdentityWeakReference

请注意，jmap 命令会强制执行 FullGC。

JVM settings:
export JVM_OPT="\
-d64 \
-Xms200m -Xmx200m \
-XX:MaxNewSize=64m \
-XX:NewSize=64m \
-XX:+UseParNewGC \
-XX:+UseConcMarkSweepGC \
-XX:MaxTenuringThreshold=10 \
-XX:SurvivorRatio=2 \
-XX:CMSInitiatingOccupancyFraction=60 \
-XX:+UseCMSInitiatingOccupancyOnly \
-XX:+CMSParallelRemarkEnabled \
-XX:+DisableExplicitGC \
-XX:+CMSClassUnloadingEnabled \
-XX:+PrintGCTimeStamps \
-XX:+PrintGCDetails \
-XX:+PrintTenuringDistribution \
-XX:+PrintGCApplicationConcurrentTime \
-XX:+PrintGCApplicationStoppedTime \
-XX:+PrintGCApplicationStoppedTime \
-XX:+PrintClassHistogram \
-XX:+ParallelRefProcEnabled \
-XX:SoftRefLRUPolicyMSPerMB=1 \
-verbose:gc \
-Xloggc:$GCLOGFILE"

---

java version "1.6.0_18"
Java(TM) SE Runtime Environment (build 1.6.0_18-b07)
Java HotSpot(TM) Server VM (build 16.0-b13, mixed mode)

Solaris 10/Sun Fire(TM) T1000 

Answer 1

已在 1.6.0_29 中修复:http://www.oracle.com/technetwork/java/javase/6u29-relnotes-507960.html?ssSourceSiteId=ocomen

1.6.0_29 没有在错误页面本身 (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6942989) 中提及，所以我认为将链接发布到那里会很有用，这样就可以发现它已被修复的事实。