[DERBY-3745] Derby can leak classloaders in an app server environment

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 10.3.3.0, 10.4.1.3, 10.5.1.1
• Fix Version/s: 10.3.3.1, 10.4.2.0, 10.5.1.1
• Component/s: Services
• Bug behavior facts: Security
• Assignee: Katherine Marsden
• Reporter: Katherine Marsden
• Created: 30/Jun/08 23:30
• Updated: 25/Aug/14 17:57
• Resolved: 25/Aug/08 20:30

Description

A user reported potential class loader leaks in Derby

...The first one looks like Derby created a long-running
thread and copying the context class loader. To fix, the
context class loader should be saved/set/restored around the
creation of the new thread so that it copies some benign class
loader instead (e.g., null or getClass().getClassLoader()):

0x42278e58 java/lang/Thread@302e302e
[truncating at running thread LEAK]

Object: 0x42278e58 java/lang/Thread@302e302e
Children:
0x42278ee0 java/lang/String@303f303f
0x4226e558 java/lang/ThreadGroup@6f2e6f2e
0x42278e40
org/apache/derby/impl/services/monitor/AntiGC@603a603a
0x419cfac0

The second is another long running thread. The same applies:

0x426fe7a0 java/lang/Thread@19901990
[truncating at running thread LEAK]

Object: 0x426fe7a0 java/lang/Thread@19901990
Parents:
0x4226e5a8 [Ljava/lang/Thread;@6f386f38
0x426fe548
org/apache/derby/iapi/services/context/ContextManager@19421942
Children:
0x426fe838 java/lang/String@19a319a3
0x4226e558 java/lang/ThreadGroup@6f2e6f2e
0x426fe4f8
org/apache/derby/impl/services/daemon/BasicDaemon@19381938
0x419cfac0

The third is a TimerThread owneed , which is created when a
Timer is created. The same applies:

0x425ac538 java/util/Timer$TimerImpl@6b8a6b8a
[truncating at running thread LEAK]

Object: 0x425ac538 java/util/Timer$TimerImpl@6b8a6b8a
Parents:
0x41faaf58 [Ljava/lang/Thread;@3c583c58

Object: 0x425ac510 java/util/Timer@6b856b85
Parents:
0x425ac500
org/apache/derby/impl/services/timer/SingletonTimerFactory@56e25
6e2

For more info, see thread at:
http://www.nabble.com/ClassLoader-leaks--td18121374.html

Issue Links

• is related to: DERBY-3887 Embedded Derby fails under JBoss because of JMX-related conflicts
• is related to: DERBY-6619 After silently swallowing SecurityExceptions, Derby can leak class loaders
• relates to: DERBY-3803 'org.apache.derbyTesting.functionTests.tests.lang.XMLTypeAndOpsTest' failures on JVM 1.5 on trunk, 10.4 and 10.3