[logback-dev] [JIRA] Updated: (LBCORE-67) Unsecure usage of locks in AppenderAttachableImpl

[Joern Huxhorn (JIRA)]

     [ http://jira.qos.ch/browse/LBCORE-67?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Joern Huxhorn updated LBCORE-67:
--------------------------------

    Attachment: LockPatchWithTest.patch

Ok, I implemented to deadlock-tests. While it's not a realistic test the same situation could definitely happen in production in case of OutOfMemoryError as I wrote in the comment of the test.

It's generally a very bad idea to save a bit of standard code just because a possible problem isn't imaginable at the moment. I'm not even sure if the code without try {} finally {} will execute faster or if there won't be any difference at all.

This is one of the cases where I'll really welcome closures in java because those will eliminate this shortcoming, i.e. the manual handling of locks.

In the future, code will look like this:

lock(readLock)
{
  // do something
}

instead of 

readLock.lock();
try
{
  // do something
}
finally
{
  readLock.unlock();
}

but in the meantime we'll just have to stick to conventions.

> Unsecure usage of locks in AppenderAttachableImpl
> -------------------------------------------------
>
>                 Key: LBCORE-67
>                 URL: http://jira.qos.ch/browse/LBCORE-67
>             Project: logback-core
>          Issue Type: Bug
>          Components: Appender
>    Affects Versions: 0.9.10
>            Reporter: Joern Huxhorn
>            Assignee: Logback dev list
>         Attachments: LockPatch.patch, LockPatchWithTest.patch
>
>
> The unlock of a lock should, I would even say "must", always be done in
> a finally block. Otherwise really bad things (deadlock) can happen if an exception
> is thrown.
> See http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/locks/Lock.html

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