RE: [equinox-dev] FW: Classloader problem

[Thomas Watson <tjwatson@xxxxxxxxxx>]

You conclusion sounds reasonable (fix your manifests to import the necessary packages). PDE still needs work to give you adequate warnings/errors when you are using JRE packages for which you have not specified a constraint on. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=164188

Tom



"Murphree, Michael" ---06/16/2009 10:48:26 AM---Hi Tom,

From:	"Murphree, Michael" <Michael.Murphree@xxxxxxxxxxxxx>
To:	"Equinox development mailing list" <equinox-dev@xxxxxxxxxxx>
Date:	06/16/2009 10:48 AM
Subject:	RE: [equinox-dev] FW: Classloader problem

---

Hi Tom,
 
We've been experimenting with the following properties:
 
osgi.compatibility.bootdelegation=false
org.osgi.framework.bootdelegation=\
            com.ibm.jsse2, \
            com.ibm.jvm, \
            com.ibm.lang.management, \
            com.ibm.misc, \
            com.ibm.nio.cs, \
            com.ibm.oti.*, \
            com.ibm.security.*, \
            com.sun.jmx.*, \
            javax.crypto, \
            javax.crypto.spec, \
            javax.management, \
            javax.management.*, \
            javax.naming, \
            javax.naming.*, \
            javax.net.ssl, \
javax.security.*, \
            javax.sql, \
javax.swing, \
javax.swing.*, \
            sun.awt, \
            sun.beans.editors, \
            sun.io, \
            sun.management.*, \
            sun.misc, \
            sun.net, \
            sun.net.*, \
            sun.nio.*, \
            sun.reflect, \
            sun.reflect.*, \
            sun.rmi.*, \
            sun.security.*, \
            sun.text, \
            sun.text.resources, \
            sun.util.*
 
We've omitted the following from the list:
            javax.xml
            javax.xml.*
            org.w3c.dom
            org.xml.sax
            org.xml.sax.helpers
 
We had hoped to have our bundles use the XML bundles present in our stack.  We include the Orbit jar javax.xml_1.3.4.v200801282000.jar which exports javax.xml.*, org.w3c.dom.* and the SAX packages.  When we include this restriction to the classloading, we find our collection of bundles will not start (although Equinox does), be it on J9 or the Sun VM.
 
For example, we are using PAX Logging bundles which include Log4J.  Log4J code wants to parse its XML configuration files, yet the bundle it is in does not import any of the XML packages.  Our thinking is that it is receiving these XML packages implicitly through boot classloader delegation.  When this restriction is lifted (the default condition) the bundle works fine and is able to start and parse its configuration files.  In J9, however, we have other bundles that refuse to work when the XML packages are permitted to come from boot classloader delegation.
 
While we believe this is now a development issue on our part (fix our manifests), do our conclusions hold water?  Is there something else we ought to try?
 
Additionally, is there something in the Eclipse IDE we can do to have it warn us when our bundles get their XML goodies from the JRE instead of other bundles?
 
Regards,
 
Michael Murphree
Compuware Corporation
 
 
 
From: equinox-dev-bounces@xxxxxxxxxxx [mailto:equinox-dev-bounces@xxxxxxxxxxx] On Behalf Of Thomas Watson
Sent: Friday, June 05, 2009 3:52 PM
To: Equinox development mailing list
Subject: Re: [equinox-dev] FW: Classloader problem

Are you setting the configuration property "org.osgi.framework.bootdelegation=*"? What version of Equinox do you use? Anything version 3.3 or later should not be delegating class loads to the VM first by default (unless you set explicitly set org.osgi.framework.bootdelegation=*). If you use Import-Package for some org.apache.* package and you get resolved to an export from a bundle then you should load the content of the package from that bundle.

There is also a compatibility mode Equinox uses by default to delegate to the parent (boot) class loader as a last resort if a class or resource cannot be found by normal OSGi delegation. See osgi.compatibility.bootdelegation in Eclipse help. If you set this configuration property to false then this last resort delegation is disabled. But even with this compatibility mode enabled you should be able to load org.apache classes from the installed bundles instead of from the VM by default. If you think Equinox is configured correctly in your environment then I suggest you open a bug against Equinox and give us steps to reproduce. Thanks.

Tom



"O'Flynn, Dennis" ---06/05/2009 12:34:09 PM---Anyone have any experience running Equinox using IBM J9? We are having some problems with using IBM J9 that we don’t encounte

From:	"O'Flynn, Dennis" <Dennis.OFlynn@xxxxxxxxxxxxx>
To:	"Equinox development mailing list" <equinox-dev@xxxxxxxxxxx>
Date:	06/05/2009 12:34 PM
Subject:	[equinox-dev] FW: Classloader problem

---

Anyone have any experience running Equinox using IBM J9? We are having some problems with using IBM J9 that we don’t encounter with Sun’s JVM.

See below…

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From: Hawkins, Joel
Sent: Friday, June 05, 2009 1:27 PM
To: O'Flynn, Dennis
Subject: Classloader problem

Dennis -

In a nutshell - The J9 VM packages many javax xml extension jars and their corresponding apache implementations in the library directory of the JRE. Many of the same packages are supplied by bundles that ship with Eclipse. A number of these bundles export packages without version numbers, and we find ourselves running into class verification errors when the classes provided by the JRE don't match those expected by the bundles. The Sun JVM prepend the apache classes with com.sun., so the problem is partially mitigated. However, for javax.* classes, the potential for trouble remains.

Is there a way to alter the contents of the system classpath during osgi startup such that we can suppress these additional classes provided by J9 and resolve them from the bundles provided by Eclipse?

Cheers,

Joel

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