[KARAF-4769] NPE when executing threads --tree shell command

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 3.0.5
• Component/s: karaf

Environment

CentOS 7 x86_64, OracleJDK 1.8.0_101-b13

• Assignee: Unassigned
• Reporter: Richard Kosegi
• Created: 15/Oct/16 07:44
• Updated: 15/Sep/18 16:35

Description

There is probably race condition in "thread" shell command (Karaf 3.0.5).
When command "threads --tree" is executed repeatedly and very often, following NPE is logged to console:

2016-10-15 09:34:46,712 | ERROR | l for user karaf | ShellUtil | 27 - org.apache.karaf.shell.console - 3.0.5 | Exception caught while executing command
java.lang.NullPointerException
at org.apache.karaf.shell.commands.impl.ThreadsAction$ThreadData.isInteresting(ThreadsAction.java:241)
at org.apache.karaf.shell.commands.impl.ThreadsAction$ThreadGroupData.printTree(ThreadsAction.java:179)
at org.apache.karaf.shell.commands.impl.ThreadsAction$ThreadGroupData.printTree(ThreadsAction.java:176)
at org.apache.karaf.shell.commands.impl.ThreadsAction$ThreadGroupData.print(ThreadsAction.java:166)
at org.apache.karaf.shell.commands.impl.ThreadsAction.doExecute(ThreadsAction.java:117)
at org.apache.karaf.shell.console.AbstractAction.execute(AbstractAction.java:33)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.karaf.shell.commands.basic.AbstractCommand.execute(AbstractCommand.java:33)[27:org.apache.karaf.shell.console:3.0.5]
at Proxy8fbde0d3_4461_4b6a_ace2_2b1a61886abd.execute(Unknown Source)[:]
at Proxy8fbde0d3_4461_4b6a_ace2_2b1a61886abd.execute(Unknown Source)[:]
at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:78)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:480)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:406)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:182)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:119)[27:org.apache.karaf.shell.console:3.0.5]
at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:94)
at org.apache.karaf.shell.console.impl.jline.ConsoleImpl.run(ConsoleImpl.java:210)
at org.apache.karaf.shell.console.impl.jline.LocalConsoleManager$2$1$1.run(LocalConsoleManager.java:109)
at java.security.AccessController.doPrivileged(Native Method)[:1.8.0_101]
at org.apache.karaf.jaas.modules.JaasHelper.doAs(JaasHelper.java:57)[28:org.apache.karaf.jaas.modules:3.0.5]
at org.apache.karaf.shell.console.impl.jline.LocalConsoleManager$2$1.run(LocalConsoleManager.java:102)[27:org.apache.karaf.shell.console:3.0.5]

This problem is not often reproducible.