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From "Sebb (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LANG-204) [lang] org.apache.commons.lang.Entities multithreaded init.
Date Wed, 03 Feb 2010 01:29:18 GMT

    [ https://issues.apache.org/jira/browse/LANG-204?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12828878#action_12828878
] 

Sebb commented on LANG-204:
---------------------------

The code is still not thread-safe, as the various nested classes are not thread-safe.

However, provided that the XML and other static Entities are not updated externally it seems
the static methods ought to be thread-safe.
The only issue is whether the data items are published correctly to all threads. 
I thought that was guaranteed for static fields, but perhaps that was not the case before
Java 5.
In which case it might be worth using temporary variables to populate the Entities in the
static blocks, and assign the static field at the end.

It's a pity that the static Entries are not immutable once created. Perhaps they could be
wrapped?

> [lang] org.apache.commons.lang.Entities multithreaded init.
> -----------------------------------------------------------
>
>                 Key: LANG-204
>                 URL: https://issues.apache.org/jira/browse/LANG-204
>             Project: Commons Lang
>          Issue Type: Improvement
>          Components: lang.*
>    Affects Versions: 2.1
>         Environment: Operating System: other
> Platform: Other
>            Reporter: Gary Gregory
>            Priority: Minor
>             Fix For: 2.x
>
>
> -----Original Message-----
> From: Gaulin, David: #CIPO - OPIC [mailto:Gaulin.David@ic.gc.ca] 
> Sent: Wednesday, April 26, 2006 5:09 AM
> To: commons-dev@jakarta.apache.org
> Subject: [lang] org.apache.commons.lang.Entities
> Hello,
> Not sure if it is the right mailling list but here we go anyway.
> I am currently using the Entities.java class (well I am using the
> StringEscapeUtils.java which uses that class).  Works really good, saved me a
> lot of time.  My thanks to the people who wrote it.
> I have encountered a little problems with it taught.  Nothing major but I just
> taugth I would share since it migth be of interest to you.
> I have an heavily multithreaded process that runs on a really under powered
> server.  All those threads access the StringEscapeUtils.escapeXml() methods
> pretty much at the same time.  What happens is that by the time the Second or
> Third Thread calls the StringEscapeUtils.escapeXml() the static initialization
> in the Entities.java class has not completed yet.  That block in particular.
>     static {
>         XML = new Entities();
>         XML.addEntities(BASIC_ARRAY);
>         XML.addEntities(APOS_ARRAY);
>     }
> I don't get a NullPointer so it seems that XML = new Entities() is actually
> being executed before the other Thread starts but the
> XML.addEntities(BASIC_ARRAY) on the other hand is not executed before the other
> thread starts.  So when the second or third thread calls the
> StringEscapeUtils.escapeXml() it doesn't escape the BASIC_ARRAY or APOS_ARRAY
> entities.  To fix it, in my code, I just make sure to call
> StringEscapeUtils.escapeXml() before I start any threads and it solve the
> problems but if anyone is ever to re-work the class this might be something to
> look at.
> Just to share.
> Thank
> David

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