Re: Trying to embed gnu.xml.dom.DomDocumentBuilderFactory

[Andrew Haley <aph at littlepinkcloud dot COM>]

Mohsen Saboorian writes:
 > Thanks,
 > There was no DomDocumentBuilderFactory entry in the output of command:
 > nm --demangle=java myapp.exe
 > even when I explicitly imported and did "new
 > DomDocumentBuilderFactory()" in the code.
 > 
 > I extracted a portion of libgcj-4.2.0.jar (the whole content of
 > gnu.xml.* package), say gcj-dom.jar, and compiled and linked it with
 > my application. The result executable has DomDocumentBuilderFactory
 > but this time I'm facing with NoClassDefFoundError for
 > gnu.xml.dom.DomImpl.
 > Again I put the trivial code new DomImpl() and linked the app. This
 > time again I'm facing with:
 > 
 > java.lang.NoClassDefFoundError: gnu.xml.dom.DomImpl
 > java.lang.Class.initializeClass(zekr_static_olpc.exe)
 > gnu.xml.dom.ImplementationSource.<clinit>(zekr_static_olpc.exe)
 > java.lang.Class.initializeClass(zekr_static_olpc.exe)
 > java.lang.Class.newInstance(zekr_static_olpc.exe)
 > org.w3c.dom.bootstrap.DOMImplementationRegistry.newInstance(zekr_static_olpc.exe)
 > gnu.xml.dom.DomDocumentBuilderFactory.<init>(zekr_static_olpc.exe)
 > net.sf.zekr.engine.xml.XmlReader.<init>(zekr_static_olpc.exe)
 > net.sf.zekr.common.config.ApplicationConfig.extractLangProps(zekr_static_olpc.exe)
 > ...
 > 
 > It's strange that although there exists some entry for gnu.xml.dom.DomImpl with:
 > nm --demangle=java myapp.exe
 > it gives me that error.
 > 
 > I should also say that I tried to embed xercesImpl.jar with my app, setting:
 > javax.xml.parsers.DocumentBuilderFactory=org.apache.xerces.jaxp.DocumentBuilderFactoryImpl
 > so that it uses xerces instead of gnu.xml.*. It gives me again a
 > NoClassDefFoundError.
 > 
 > It seems that even when a class file is embedded in a static binary,
 > class loader (java.lang.Class.initializeClass()) cannot load that.

I think this is a bug in libgcj.  The NoClassDefFoundError is
reporting the wrong missing class.  It's actually one of
DomDocumentBuilderFactory's dependencies that isn't being found.  If
you use "jcf-dump -v" on the class you'll see what its dependencies
are.

I'm sorry this is turning into such a PITA.

Andrew.