Thread: [Php-java-bridge-users] Classpath for external lib in JavaBridge app

Hi there,

I am quite new to Java and Tomcat webserver. I am using Tomcat 6.x. I use
Jasper reports with PHP.

After I have deployed the JavaBridge (6.x) I wanted to load all my jasper
and scriptlet libraries to a subfolder in WEB-INF/lib folder for
ex: WEB-INF/lib/jasper3.0.0/

But the libraries were never loaded by the application and I have got many
class not found errors.

Once I have moved all the classes to WEB-INF/lib/ folder the errors are
gone.

I wanted to organize all my libraries properly instead of mixing in just one
folder.

In earlier versions I can use java_require but it seems not possible now
with the version 6.x & >

Please help me know how to achieve this.

Thanks,

Hameed
Development Manager
Pilot Simple Software
Hong Kong

ha...@pi...

Hi Hameed,


> I wanted to organize all my libraries properly instead of mixing in just one
> folder.

Java 7 may contain a module system. Until then please put all Java
libraries into *one* directory.

Please see our FAQ entries "Why has java_require() been deprecated?"
and "Why do I get a NoClassDefFoundError?" for details.

There were several Java module system (better: "package system")
proposals. The one I liked best was the system implemented by
rice.edu. An introduction is here:
http://www.cs.rice.edu/~javaplt/papers/sac2007.pdf

BTW: Kent Dybvik has shown that it is possible to implement a module
system using pure syntax. Since PHP doesn't have a REPL (its top-level
environments cannot be changed by user-interaction), it makes sense to
implement such a system in place of the current PHP "namespaces"
implementation, especially since PHP namespaces doesn't allow a
re-export of (aliased) bindings: it isn't possible to build a
"compound-namespace" (see "published interfaces" vs. "public
interfaces").


Regards,
Jost Bökemeier

Hi Jost,

Thanks a lot for your info on my question. I understand about the lack of
module system in java.

In my case we have many php applications on one server using different
versions of Jasper Reports Libraries. So if I put all the versions of
libraries in one WEB-INF/lib/ folder then I believe it would cause issues on
loading correct libraries. In this case can I have two JavaBridge
applications running in my Tomcat server so that the libraries are not
messed up? If that is fine then could you please tell me how I can make two
instance of the same application? If it's simply deploying the application
twice then that's easy but if I need to change any settings to make it work
I am not sure how can I do that.

Please help.

Thanks a lot.

Best regards,
Hameed




On Thu, Mar 25, 2010 at 1:05 AM, <
php...@li...> wrote:

> Hi Hameed,
>
>
> > I wanted to organize all my libraries properly instead of mixing in just
> one
> > folder.
>
> Java 7 may contain a module system. Until then please put all Java
> libraries into *one* directory.
>
> Please see our FAQ entries "Why has java_require() been deprecated?"
> and "Why do I get a NoClassDefFoundError?" for details.
>
> There were several Java module system (better: "package system")
> proposals. The one I liked best was the system implemented by
> rice.edu. An introduction is here:
> http://www.cs.rice.edu/~javaplt/papers/sac2007.pdf
>
> BTW: Kent Dybvik has shown that it is possible to implement a module
> system using pure syntax. Since PHP doesn't have a REPL (its top-level
> environments cannot be changed by user-interaction), it makes sense to
> implement such a system in place of the current PHP "namespaces"
> implementation, especially since PHP namespaces doesn't allow a
> re-export of (aliased) bindings: it isn't possible to build a
> "compound-namespace" (see "published interfaces" vs. "public
> interfaces").
>
>
> Regards,
> Jost Bökemeier
>
>
> ------------------------------------------------------------------------------
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> php-java-bridge-users mailing list
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>



-- 
Hameed
Development Manager
Pilot Simple Software
Hong Kong

ha...@pi...

Hi,


> In my case we have many php applications on one server using different
> versions of Jasper Reports Libraries.

The example JavaBridge.war from the php-java-bridge_documentation.zip
download contains the OSGI framework. It uses separate classloaders,
similar to our deprecated java_require() feature, to allow loading
different library versions at a time. But since it has the same
issues, I cannot recomment it either. For example we ran into several
class-loading issues while preparing the BIRT report example.


> loading correct libraries. In this case can I have two JavaBridge
> applications running in my Tomcat server so that the libraries are not
> messed up?

Yes. Tomcat separates all web applications using different class
loaders. You may run into PermGenSpace OutOfMemoryErrors and some
libraries should not be loaded this way; see
http://tomcat.apache.org/tomcat-5.5-doc/RELEASE-NOTES.txt section "Web
application reloading and static fields in shared libraries". But if
you don't load too many libraries and if the library authors have
payed attention [1], this will work.

Regards,
Jost Bökemeier

[1] log4j contained such a bug:
http://marc.info/?l=log4j-user&m=109578379927175&w=2

Hello!

"If it's simply deploying the application twice"


Look here: http://php-java-bridge.sourceforge.net/pjb/user-contributed/JavaEchoServer.gif


Peter