On Sat, 13 Jul 2002, Thierry Thelliez wrote:
> Date: Sat, 13 Jul 2002 19:46:36 -0600
> From: Thierry Thelliez <[EMAIL PROTECTED]>
> Reply-To: Tomcat Users List <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
> To: 'Tomcat Users List' <[EMAIL PROTECTED]>
> Subject: RE: ClassCast exception
>
>
> More details to the problem described in the first email.
>
> I have now tried another scenario:
>
> My parent class (B) is now sitting in a jar in WEB-INF/lib.
> My subClass (A) is in a .class in WEB-INF/classes.
> B and A are in different packages (p1.x.B and p2.A).
>
> The code with the casting issue is in a static method of A.
>
> B b = doSomething(); -> Works
>
> log("B " + b.getClass().getName()); -> p1.x.B
> log("B " + b.getClass().getClassLoader()); -> CL1
>
> log("A " + A.class.getClassLoader()); -> CL2 (seems to be =
> to CL1)
>
That will generally be true -- the container sets up a single class loader
for everything in WEB-INF/classes and WEB-INF/lib.
> ( b.getClass().getClassLoader()) ==
> Class.forName("p2.A").getClassLoader())); -> true
>
> ( b.getClass().getClassLoader()) ==
> Class.forName("A").getClassLoader())); -> Class not found...
This is never going to work. The argument to Class.forName has to be the
fully qualified class name. See the Javadocs on java.lang.Class for more.
>
> A a = (A) doSomething(); ->
> ClassCastException...
>
>
>
> I have been through extensive web search. It seems that this problem is
> not uncommon but I cannot figure out how to solve it...
>
> (How do you get the instance id for the ClassLoaders? In the output in
> my first email, my class loaders are giving me a name, not a unique id)
>
> Help!
>
> Thierry
>
Craig
> -----Original Message-----
> From: Thierry Thelliez [mailto:[EMAIL PROTECTED]]
> Sent: Saturday, July 13, 2002 6:04 PM
> To: [EMAIL PROTECTED]
> Subject: ClassCast exception
>
> Hello,
>
> I have a ClassCast problem. I read the archive and attempted few
> suggestions (like grouping everything in one jar in WEB-INF/lib) without
> success.
>
> I am using tomcat 4.0.4 and 1.3.1_02 under Solaris.
>
> Someone suggested looking at the ClassLoaders. The following is
> generated by something like:
> Log4j("MyClass " + MyClass.class.getClassLoader());
>
> --------------------------------------------------------------------
> 2002-07-13 18:36:56,808 - - MyClass WebappClassLoader
> available:
> delegate: false
> repositories:
> required:
> ----------> Parent Classloader:
> StandardClassLoader
> available:
> delegate: true
> repositories:
> file:/serverPath/jakarta-tomcat-4.0.4/classes/
> file:/serverPath/jakarta-tomcat-4.0.4/lib/jasper-runtime.jar
> file:/serverPath/jakarta-tomcat-4.0.4/lib/jasper-compiler.jar
> file:/serverPath/jakarta-tomcat-4.0.4/lib/naming-factory.jar
> required:
> ----------> Parent Classloader:
> StandardClassLoader
> available:
> Extension[javax.mail, implementationVendor=Sun Microsystems, Inc.,
> implementationVendorId=com
> .sun, implementationVersion=1.2, specificationVendor=Sun Microsystems,
> Inc., specificationVersion
> =1.2]
> delegate: true
> repositories:
> file:/serverPath/jakarta-tomcat-4.0.4/common/classes/
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/naming-common.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/servlet.jar
>
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/naming-resources.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/jdbc2_0-stdext.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/activation.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/jta-spec1_0_1.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/xerces.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/tyrex-0.9.7.0.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/mail.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/jndi.jar
> file:/serverPath/jakarta-tomcat-4.0.4/common/lib/cos.jar
> required:
> ----------> Parent Classloader:
> sun.misc.Launcher$AppClassLoader@3f52a5
>
>
> ---------------------------------
>
> just after that I try a Class.forName("MyClass");
> but I get a ClassNotFound exception.
>
>
> Is that normal that I don't see listed the webapps/myApp/WEB-INF/lib in
> the repositories above?
>
> In the ClassCast issue, both classes return the same loader.
>
> Thanks,
> Thierry
>
>
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