So, I've gone back and double-checked as much as I can (Tomcat version, JDK
version), and the classpath, and I have identical classpaths in both
environments (except the sort order of the URLs per "level" of
ClassLoader), and I've re-verified the behaviour:
- fails in the docker environment
- works locally
(Same WAR file on both).
I guess I'm in to one of the following approaches next:
- build a debug version of Tomcat, and step through the code that breaks
and see if I can figure out why (not that I have time to do this of
course...but might be necessary)
- construct a trivial application reproduction, along with docker layout,
and see if anyone else can reproduce... (assuming anyone else has time to
do that of course...)
Anyone got any suggestions of what to look into next?
On Mon, Feb 7, 2022 at 5:05 PM Rob Sargent <rsarg...@xmission.com> wrote:
>
>
> On 2/7/22 14:50, Robert Turner wrote:
> > All
> >
> > I'm hoping that someone can point me in the right direction as this issue
> > has been baffling me all day, and I'm starting to run out of ideas of
> what
> > to look at next.
> >
> > The logic below is working without issue until I move our test
> environment
> > into a Docker container. I'm using the same Tomcat version, and the same
> > JDK in both the container and the non-container environments.
> >
> >
> > I've got some EL in a JSP page, for example (simplified):
> >
> > <p>${class1.field}</p>
> >
> >
> > And an attribute is set on the page context as follows:
> >
> > final package1.Class1 objectValue = ...; // either value object of Class1
> > or null
> > pageContext.setAttribute("class1", objectValue);
> >
> >
> > Now, when objectValue is pointing to a valid object, everything is okay.
> > But when objectValue is null, this is where things get peculiar (and I
> get
> > both a working and non-working behaviour in the different environments).
> >
> > I can easily work around the issue by changing the EL to:
> >
> > <p>${not empty class1 ? class1.field : ''$}</p>
> >
> > But it is my understanding that EL should handle nulls on it's own, and
> > this shouldn't be necessary.
> >
> >
> > In the failure situation in the docker container, I'm seeing a
> > NoClassDefFoundError exception for "package1/Class1" below [1] during the
> > JSP page "rendering". Things work fine outside the docker container.
> >
> >
> > It might be worth noting that in my case, the attribute name is of the
> same
> > name as the actual class (with the first letter being lowercase for the
> > attribute instead of uppercase in the class).
> >
> > Note that I've also replaced my actual package name and class names with
> > "package1" and "Class1", and the attribute name with "class", but they
> > translate 1-to-1 as in what I've provided here and do not use reserved
> > names.
> >
> >
> > I've done a bit of digging into the EL scope resolution code in Tomcat,
> and
> > I'm suspecting it might be related to how it chooses the scope of the
> > object. Possibly related to maybe looking for static aspects of the
> class,
> > or something like that. After reviewing the Servlet / JSP / EL
> > documentation, I also haven't found anything obvious that would suggest
> > what the problem might be.
> >
> > Hopefully someone has encountered this before and can nudge me in the
> right
> > direction.
> >
> > Thanks in advance,
> >
> > Robert
> >
> >
> >
> > [1]
> > Caused by: java.lang.NoClassDefFoundError: package1/Class1 (wrong name:
> > package1/class1)
> > at java.base/java.lang.ClassLoader.defineClass1(Native Method)
> > at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
> > at
> >
> java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
> > at
> >
> org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2478)
> > at
> >
> org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:870)
> > at
> >
> org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1371)
> > at
> >
> org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1215)
> > at javax.el.ImportHandler.findClass(ImportHandler.java:477)
> > at javax.el.ImportHandler.resolveClass(ImportHandler.java:421)
> > at
> >
> javax.servlet.jsp.el.ScopedAttributeELResolver.getValue(ScopedAttributeELResolver.java:85)
> > at
> org.apache.jasper.el.JasperELResolver.getValue(JasperELResolver.java:124)
> > at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:93)
> > at org.apache.el.parser.AstValue.getValue(AstValue.java:136)
> > at org.apache.el.parser.AstFunction.getValue(AstFunction.java:188)
> > at
> org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
> > at
> >
> org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:692)
> > at
> >
> And you're sure package1 is on the classpath of the docker version?
>
>
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