Re: Change in properties for logging: deliberate?

[Daniel Fuchs]

Hi Jeremy,

I will propose a fix then.

However be aware that logging configuration files that use ".handlers"
instead of "handlers" to configure the root logger are fragile, as it
seems that any subsequent call to LogManager.readConfiguration() will
remove this configuration. Though I agree this might not be an issue
if it has stayed unnoticed for 15 years.

I will need to verify the behavior of ".level".
Thanks for pointing that out. I don't think it has the same flaw but
I will need to make sure.

best regards,

-- daniel

On 10/11/17 20:48, Jeremy Manson wrote:

Daniel,

Thanks for taking a look at this.  I'd like to disagree with the reasoning here.

First, it isn't just JDKs 7 and 8 - the behavior is the same all the way back to JDK 1.4, when the java.util.logging API was introduced.  So changes affect 15 years' worth of logging configuration files.  For example, there are no fewer than 350 instances of this pattern in our codebase.  Imagine multiplying that across the entire world - everyone who is doing this has to change their configuration.  That's a pretty big cost to introduce on the developer community.

This is worse on legacy systems, because the handlers property was broken for a long time, and people basically had to use .handlers: http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6207335.

Second, it is inconsistent for ".level" to work for level for the root logger, and ".handlers" not to work for handlers for the root logger. The empty string represents the root logger, and having it only represent the root logger sometimes is (to me) counterintuitive. Without checking, my suspicion is that .level behaves the same way as .handlers (that is, it is only loaded once).  If we can live with the inconsistency there, we can live with it here.  You can even document that that is the difference.

Jeremy

On Fri, Nov 10, 2017 at 8:04 AM, Daniel Fuchs <daniel.fu...@oracle.com <mailto:daniel.fu...@oracle.com>> wrote:

    Hi Jason,

    I have done a few tests with JDK 8 & 7.

    I have created custom handlers and added some
    debug traces in their constructors and debug methods.

    Then I have added these two lines to my logging.properties:

    handlers = custom.Handler
    .handlers = custom.DotHandler

    What I see is this:

    - the first time the configuration is read, two handlers
       are added to the root logger:
       - an instance of DotHandler (first), then an instance
         of Handler (second).

    Then if you call LogManager.readConfiguration() again,
    both handlers are closed, and this time only one
    instance of Handler is added to the root logger.
    No instance of DotHandler is added.
     From now on the property is ignored.

    This is because the root logger is a special beast:
    it will not be removed (like all other loggers) when
    LogManager.readConfiguration() is called.

    And as it happens, handlers are added to loggers
    when the loggers are added to the LogManager.
    As it happens, the ".handlers" property is only parsed
    and read when the root logger is added to the LogManager,
    and thus only once.

    The "handlers" property on the other hand is parsed
    every time LogManager.readConfiguration() is called.

    Given that, I suspect we should deprecate the use of
    ".handlers" for the root logger, as it appears that
    it has never worked properly. I could work on a patch
    for 10 (possibly backport it to 9 update) to preserve
    the strange behavior of 7 & 8, but is it worth it?

    What are your thoughts?

    best regards,

    -- daniel





    On 09/11/2017 19:50, Jason Mehrens wrote:

        Daniel,

        I would assume you would fix since it is advertised as a feature
        over here:
        https://docs.oracle.com/javase/1.5.0/docs/guide/logging/changes.html
        <https://docs.oracle.com/javase/1.5.0/docs/guide/logging/changes.html>

        If it helps, I've dug up a lot of the history on this over here
        a while back:
        
https://stackoverflow.com/questions/36726431/in-a-java-util-logging-logging-properties-file-whats-the-difference-between-h
        
<https://stackoverflow.com/questions/36726431/in-a-java-util-logging-logging-properties-file-whats-the-difference-between-h>

        I've updated that to include the links to this new issue.  Now
        that I've linked this message thread to that message thread that
        should crash the internet. :)

        Jason

        ________________________________________
        From: core-libs-dev <core-libs-dev-boun...@openjdk.java.net
        <mailto:core-libs-dev-boun...@openjdk.java.net>> on behalf of
        Daniel Fuchs <daniel.fu...@oracle.com
        <mailto:daniel.fu...@oracle.com>>
        Sent: Thursday, November 9, 2017 1:29 PM
        To: mandy chung
        Cc: core-libs-dev@openjdk.java.net
        <mailto:core-libs-dev@openjdk.java.net>
        Subject: Re: Change in properties for logging: deliberate?

        On 09/11/2017 19:16, mandy chung wrote:

            Daniel - we should add this known issue in the release note
            and document
            the workaround.


        Hi Mandy,

        Right, it either need to be fixed, or documented in the release
        notes. Let me first have a look at the issue though.

        best regards,

        -- daniel