4 Replies Latest reply on Dec 3, 2009 1:34 PM by zman12345

What is a meaning of :0.0.0 on classloader bean name?

zman12345 Dec 3, 2009 9:42 AM

Hi,

In JBoss5's conf/bootstrap/jmx.xml for example, I see lines like these:

<classloader><inject bean="jmx-classloader:0.0.0"/></classloader>

 <classloader name="jmx-classloader" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true">
 <root>${jboss.lib.url}jboss-j2se.jar</root>
 <root>${jboss.lib.url}jboss-mbeans.jar</root>
 <root>${jboss.lib.url}jboss-jmx.jar</root>
 <root>${jboss.lib.url}jboss-system-jmx.jar</root>
 <root>${jboss.lib.url}dom4j.jar</root>
 </classloader>

What is the meaning of 0.0.0 in bean="jmx-classloader:0.0.0"?

Thanks,
-Z

1. Re: What is a meaning of :0.0.0 on classloader bean name?

alesj Dec 3, 2009 10:36 AM (in response to zman12345)
"zman12345" wrote:

What is the meaning of 0.0.0 in bean="jmx-classloader:0.0.0"?

From the classloader element you posted
<classloader name="jmx-classloader" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true"> <root>${jboss.lib.url}jboss-j2se.jar</root> ...

a ClassLoader bean is created.
And his default name (if you don't explicitly set it -- via context attribute) is name:version.
And since also no version is specified, the version defaults to 0.0.0.
OK?
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2. Re: What is a meaning of :0.0.0 on classloader bean name?

zman12345 Dec 3, 2009 11:00 AM (in response to zman12345)
Hi Ales,

So are all bean elements in deployment follows this name:version rule or just for classloader's name specific? Would you be so kind to point me to doc that talks about this behavior?

I experiment couple variation of names and it doesn't follow your explanation.

1) If 0.0.0 is default, then I assume using it is optional, but remove it here fails to start server:
<classloader><inject bean="jmx-classloader"/></classloader>

2) If 0.0.0 is the default, and I were to change it to something else, it doesn't work.
<classloader><inject bean="jmx-classloader:0.0.99"/></classloader> <classloader name="jmx-classloader:0.0.99" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true"> ...

Also what is the benefit of using "name:version" format vs where a user explicitly creating two unique names? When should I use one and not the other?

Thanks,
-Z
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3. Re: What is a meaning of :0.0.0 on classloader bean name?

alesj Dec 3, 2009 11:14 AM (in response to zman12345)
"zman12345" wrote:

So are all bean elements in deployment follows this name:version rule or just for classloader's name specific?

Just classloader bean from classloader element.

"zman12345" wrote:

Would you be so kind to point me to doc that talks about this behavior?

* http://anonsvn.jboss.org/repos/jbossas/projects/jboss-cl/trunk/classloading-vfs/src/main/java/org/jboss/classloading/spi/vfs/metadata/VFSClassLoaderFactory.java

"zman12345" wrote:

I experiment couple variation of names and it doesn't follow your explanation.

It does. It's either
* you didn't understand me
* my explanation wasn't very good

"zman12345" wrote:

1) If 0.0.0 is default, then I assume using it is optional, but remove it here fails to start server:
<classloader><inject bean="jmx-classloader"/></classloader>

No, it's default in classloader element.
Plain inject element is completely generic, doesn't know or care about versioning.

"zman12345" wrote:

2) If 0.0.0 is the default, and I were to change it to something else, it doesn't work.
<classloader><inject bean="jmx-classloader:0.0.99"/></classloader> <classloader name="jmx-classloader:0.0.99" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true"> ...

That's the same as before, you just added 0.0.99 at the end.
If you wanna use 0.0.99 in inject, you should change classloader element's version attribute (version="0.0.99").

"zman12345" wrote:

Also what is the benefit of using "name:version" format vs where a user explicitly creating two unique names? When should I use one and not the other?

You need some defaults for such things.
e.g. you have versioning present, why not use it

But you can override it all.
When/why ... up to you.
I don't know what you're doing, hence cannot draw any conclusions. ;-)
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4. Re: What is a meaning of :0.0.0 on classloader bean name?

zman12345 Dec 3, 2009 1:34 PM (in response to zman12345)

Thank you for the reply Ales.

The version attribute did the trick. So now this works.

 <classloader><inject bean="jmx-classloader:0.0.99"/></classloader>
 <classloader name="jmx-classloader" version="0.0.99" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true">
 ...
 </classloader>

Also thanks for point to the source link. I was hoping for a more high level of explanation what the ":version" will do for me. Because I can certainly do it this way right?

 <classloader name="jmx-classloaderA" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true">
 ...
 </classloader>
 <classloader name="jmx-classloaderB" xmlns="urn:jboss:classloader:1.0" export-all="NON_EMPTY" import-all="true">
 ...
 </classloader>
 <bean name="b1">
 <classloader><inject bean="jmx-classloaderA:0.0.0"/></classloader>
 </bean>
 <bean name="b2">
 <classloader><inject bean="jmx-classloaderB:0.0.0"/></classloader>
 </bean>

So now you see that the version string is not doing anything for me, but yet I am forced to use it. Hope you see why this is a bit confusing for a beginner to pickup.

-Z

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