com/sun/org/apache/xpath/internal/* is the Oracle/Sun JAXP implementation.
That is not an Apache release. Xerces doesn't even implement
javax.xml.xpath.*.
That aside, the component you're using seems to be loading an XPathFactory
over and over again which is expensive and can result lots of ClassLoader
activity.
Thanks.
Michael Glavassevich
XML Technologies and WAS Development
IBM Toronto Lab
E-mail: mrgla...@ca.ibm.com
E-mail: mrgla...@apache.org
Eric Urban <er...@spiceworks.com> wrote on 07/17/2015 08:34:17 AM:
> Hello,
>
> I work on a Rails application that uses Nokogiri to parse HTML. We run
> on JRuby 1.7.19, so Nokogiri takes advantage of the xerces XML parser to
> do its parsing. I noticed that using Nokogiri (and thus Xerces) triggers
> tons of class loading. Through some research I found setting some Java
> system properties to sane defaults reduced the amount of class loading
> that goes on. Here is what I set
>
> java.lang.System.setProperty('javax.xml.xpath.XPathFactory:http://
> java.sun.com/jaxp/xpath/
> dom','com.sun.org.apache.xpath.internal.jaxp.XPathFactoryImpl')
>
> java.lang.System.setProperty
>
('org.apache.xerces.xni.parser.XMLParserConfiguration','org.apache.xerces.parsers.XIncludeAwareParserConfiguration')
>
> java.lang.System.setProperty
>
('com.sun.org.apache.xml.internal.dtm.DTMManager','com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault')
>
>
> This is actually set from Ruby code, but it interacts with the JVM just
> like native Java code. I figured all this out from documentation on the
> web. This reduced the amount of Jar file's that are opened dramatically
> at runtime.
>
> Using intrace to trace JarFile activity, I still get this happening
> constantly however:
>
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: {
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: {
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: Return: null
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: }
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: Return: null
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: }
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: {
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: {
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: {
> [07:16:31.004]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: Arg:
> java.util.jar.JarFile@61175d12
> [07:16:31.004]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: }
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: Return:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile:getEntry: }
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: Return:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.004]:[36]:java.util.jar.JarFile:getJarEntry: }
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: {
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: {
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: Return: null
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: }
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: Return: null
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: }
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: {
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: {
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: {
> [07:16:31.005]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: Arg:
> java.util.jar.JarFile@61175d12
> [07:16:31.005]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: Arg:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile$JarFileEntry:<init>: }
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: Return:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile:getEntry: }
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: Return:
> com/sun/org/apache/xpath/internal/jaxp/XPathFactoryImpl.class
> [07:16:31.005]:[36]:java.util.jar.JarFile:getJarEntry: }
>
> As you can see the class is finally found. The problem is, it repeats
> this for every time we invoke Nokogiri. There is a pretty sever
> performance cost from doing this.
>
> Is there any easy way to fix this? Any assistance you can provide would
> be greatly helpful. If you would like me to try and produce a contrived
> code example that replicates this, I can do that.
>
> Eric Urban
> Developer at Spiceworks
>
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