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ASF GitHub Bot commented on HADOOP-19049: ----------------------------------------- Hisoka-X commented on code in PR #6488: URL: https://github.com/apache/hadoop/pull/6488#discussion_r1470514489 ########## hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java: ########## @@ -4077,6 +4077,7 @@ private interface StatisticsAggregator<T> { STATS_DATA_CLEANER. setName(StatisticsDataReferenceCleaner.class.getName()); STATS_DATA_CLEANER.setDaemon(true); + STATS_DATA_CLEANER.setContextClassLoader(null); Review Comment: If the thread relies on the return value of `Thread.currentThread().getContextClassLoader()` for logical processing, it may encounter NPE, but I checked the corresponding code. This risk should not exist. In fact, this is a normal way of handling classloader references in the daemon thread. You can refer https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-7008595 > Class loader leak caused by StatisticsDataReferenceCleaner thread > ----------------------------------------------------------------- > > Key: HADOOP-19049 > URL: https://issues.apache.org/jira/browse/HADOOP-19049 > Project: Hadoop Common > Issue Type: Bug > Components: common > Affects Versions: 3.3.6 > Reporter: Jia Fan > Priority: Major > Labels: pull-request-available > > The > "org.apache.hadoop.fs.FileSystem$Statistics$StatisticsDataReferenceCleaner" > daemon thread was created by FileSystem. > This is fine if the thread's context class loader is the system class loader, > but it's bad if the context class loader is a custom class loader. The > reference held by this daemon thread means that the class loader can never > become eligible for GC. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org