Hi Santiago,
Thanks for looking into this.
Within the context of Apache Cocoon, I can reproduce this error
everytime. This is done by opening the same web-app in two seperate
browser windows and clicking on a link in both browsers which uses
xsltc to compile a stylesheet. That is, we initiate
two seprate (simultaneous) requests to compile a stylesheet.
As I said earler, it seems to me that the problem _may_ lie in the
apache.xalan.xsltc.trax.TemplatesHandlerImpl.java within the
getTemplates() method.
What follows is a stack trace of the error we get. Note the original
exception occurs in a static method within the BCEL code.
Is there a problem with how we are using xsltc, or is there are generic
threading issue with xsltc??
Please let me know what other information you might need.
Many thanks,
Michael Melhem
java.lang.ClassFormatError: Invalid method signature:
java/lang/String;)Ljava/lang/String;
at
org.apache.bcel.classfile.Utility.typeOfSignature(Utility.java:1019)
at org.apache.bcel.generic.Type.getType(Type.java:159)
at org.apache.bcel.generic.Type.getArgumentTypes(Type.java:221)
at
org.apache.bcel.generic.InvokeInstruction.consumeStack(InvokeInstruction.jav
a:99)
at org.apache.bcel.generic.MethodGen.getMaxStack(MethodGen.java:824)
at org.apache.bcel.generic.MethodGen.setMaxStack(MethodGen.java:717)
at
org.apache.xalan.xsltc.compiler.Mode.compileApplyTemplates(Mode.java:1047)
at
org.apache.xalan.xsltc.compiler.Stylesheet.compileModes(Stylesheet.java:447)
at
org.apache.xalan.xsltc.compiler.Stylesheet.translate(Stylesheet.java:548)
at
org.apache.xalan.xsltc.trax.TemplatesHandlerImpl.getTemplates(TemplatesHandl
erImpl.java:206)
at
org.apache.avalon.excalibur.xml.xslt.XSLTProcessorImpl.getTransformerHandler
AndValidity(XSLTProcessorImpl.java:224)
at
org.apache.cocoon.transformation.TraxTransformer.setup(TraxTransformer.java:
333)
at
org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.setupPipeli
ne(AbstractProcessingPipeline.java:390)
at
org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline
.setupPipeline(AbstractCachingProcessingPipeline.java:307)
at
org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.process(Abs
tractProcessingPipeline.java:484)
at
org.apache.cocoon.components.treeprocessor.sitemap.SerializeNode.invoke(Seri
alizeNode.java:149)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.SelectNode.invoke(SelectN
ode.java:146)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.ContainerNode.invoke(ContainerNod
e.java:68)
at
org.apache.cocoon.components.treeprocessor.sitemap.CallNode.invoke(CallNode.
java:134)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:83)
at
org.apache.cocoon.components.treeprocessor.sitemap.PreparableMatchNode.invok
e(PreparableMatchNode.java:162)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.SelectNode.invoke(SelectN
ode.java:146)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:83)
at
org.apache.cocoon.components.treeprocessor.sitemap.ActTypeNode.invoke(ActTyp
eNode.java:155)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.PipelineNode.invoke(Pipel
ineNode.java:153)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.PipelinesNode.invoke(Pipe
linesNode.java:143)t
org.apache.cocoon.components.treeprocessor.TreeProcessor.process(TreeProcess
or.java:326)
at
org.apache.cocoon.components.treeprocessor.TreeProcessor.process(TreeProcess
or.java:308)
at
org.apache.cocoon.components.treeprocessor.sitemap.MountNode.invoke(MountNod
e.java:131)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:83)
at
org.apache.cocoon.components.treeprocessor.sitemap.PreparableMatchNode.invok
e(PreparableMatchNode.java:162)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:83)
at
org.apache.cocoon.components.treeprocessor.sitemap.ActTypeNode.invoke(ActTyp
eNode.java:155)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.PipelineNode.invoke(Pipel
ineNode.java:153)
at
org.apache.cocoon.components.treeprocessor.AbstractParentProcessingNode.invo
keNodes(AbstractParentProcessingNode.java:107)
at
org.apache.cocoon.components.treeprocessor.sitemap.PipelinesNode.invoke(Pipe
linesNode.java:143)
at
org.apache.cocoon.components.treeprocessor.TreeProcessor.process(TreeProcess
or.java:326)
at
org.apache.cocoon.components.treeprocessor.TreeProcessor.process(TreeProcess
or.java:308)
at org.apache.cocoon.Cocoon.process(Cocoon.java:643)
at
org.apache.cocoon.servlet.CocoonServlet.service(CocoonServlet.java:1046)
at javax.servlet.http.HttpServlet.service(HttpServlet.java)
at org.apache.tomcat.facade.ServletHandler.doService(Unknown Source)
at org.apache.tomcat.core.Handler.invoke(Unknown Source)
at org.apache.tomcat.core.Handler.service(Unknown Source)
at org.apache.tomcat.facade.ServletHandler.service(Unknown Source)
at org.apache.tomcat.core.ContextManager.internalService(Unknown
Source)
at org.apache.tomcat.core.ContextManager.service(Unknown Source)
at
org.apache.tomcat.modules.server.Http10Interceptor.processConnection(Unknown
Source)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(Unknown Source)
at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(Unknown
Source)
at java.lang.Thread.run(Thread.java:479)
On Mon, 10 Feb 2003, Santiago Pericas-Geertsen wrote:
> Hi Michael,
> This is the first time I hear about race conditions in relation to
> BCEL. However, I think that what you're describing is indeed
> plausible (yet, it seems, never caught by our multi-threaded tests). I'm
> going to start looking into this; if you have any additional info that
> could help us isolate the problem, we'd appreciate it.
>
> Thanks.
>
> -- Santiago
> On Mon, 10 Feb 2003, Michael Melhem wrote:
>> Hi Xalan people,
>>
>> We (and some other Cocoon users) have come across a problem where if
>> effectively two threads happen to be compiling a stylesheet into
>> translet at the same time, threading issues seem to arise.
>>
>> Once the translet is intially compiled however, simultaneous access of the
>> translet is no longer a problem.
>>
>> AFAIK, the BCEL library is not thread safe by design, but there doesnt seem
>> to be any thread protection within the xsltc code that calls it. Is this case,
>> or am I missing something? Im not very familiar with the xsltc code, so
>> I was hoping that someone can enlighten me here ?
>>
>> These threading issues typically manifest themselves within static methods
>> of the bcel library.
>>
>> Re apache.xalan.xsltc.trax.TemplatesHandlerImpl.java:
>>
>> If I patch the code (that actually calls the bcel code) within the
>> getTemplates() method by adding a class-level synch block, this seems
>> to rectify the problem that we see. However, this seems like a very coarse
>> solution to me, and I dont what it means for performance issues if
>> anything.
>>
>> Many thanks,
>> Michael Melhem
>>
>>
>>
>>
>>
