[JCRRMI-28] Leaking ServerEvent objects after RMI connection loss

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.6.0, 2.1.0
• Fix Version/s: 1.6.0

Environment

Windows 7 Pro x64

32Bit Java VM
java version "1.6.0_20"
Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing)

• Assignee: Unassigned
• Reporter: Jens Theess
• Created: 18/May/10 10:08
• Updated: 04/Jun/10 09:00

Description

When an RMI connection is crashes, or the client is terminated without calling "session.logout()", the server leaks ServerEventCollection$ServerEvent objects.

Attached is a zip with two java programs that demonstrate the behaviour. Steps to reproduce:

• Open a cmd shell
• cd jcrserver
• mvn compile
• SET MAVEN_OPTS=-Djava.rmi.dgc.leaseValue=10000 && mvn exec:java -Dexec.mainClass=RMIServer

• Open another cmd shell
• cd jcrrmiclient
• mvn compile
• mvn exec:java -Dexec.mainClass=RMIClient

Watch the heap:

• Start VisualVM (you'll need the VisualVM-Sampler plugin)
• Go to the RMIServer process.
• Open the "Sampler" tab and sample "Memory".
• In the filter enter "ServerEvent".

You'll now see the number of ServerEvents (also _Stub and _Skel) steadily increasing.

• Quit the RMIClient using Ctrl-C.

The number of ServerEvents is still increasing, even after the RMI lease time expires.

If, instead of being killed, the client calls "session.logout()", the server stops producing new ServerEvent instances.