On 11/10/2011 12:59, Peter Lavin wrote:
>
> Hi Christopher, Pid, Filippo, thanks for your help. I have got this
> working as required on my Tomcat server. Here is the code that works.
>
> public class MyCustomClassLoader extends ClassLoader {
>
> public MyCustomClassLoader(ClassLoader contextClassLoader) {
> super(contextClassLoader);
> }
>
> public synchronized Class<?> arrayToClass(String name, byte[] ct,
> boolean resolve) {
> Class<?> c = defineClass(name, ct, 0, ct.length);
> try {
> this.loadClass(c.getName());
> } catch (ClassNotFoundException e) {
> e.printStackTrace();
> }
>
> if (resolve)
> System.out.println("Resolving Class in " + this.getClass());
> resolveClass(c);
>
> return c;
> }
> } // end class
>
> // This is called by...
> MyCustomClassLoader cl = new
> MyCustomClassLoader(Thread.currentThread().getContextClassLoader());
> Class<?> sp = cl.arrayToClass(null, byArray, True);
> // use the now loaded class sp for something here
>
>
> So passing the parent ClassLoader to the constructor was the key.
>
> I'm curious to know what the class
> org.apache.catalina.loader.WebappClassLoader is intended for?
>
> I was trying to do...
> MyCustomClassLoader extends org.apache.catalina.loader.WebappClassLoader{
It's the classloader the webapp uses. Extending it doesn't mean you
inherit the relationships it holds, you still have to pass in a parent
classloader in the constructor.
p
> and had to add tomcat-catalina-7.0.0.jar to my dependencies in Eclipse.
> This works in the IDE but I get the following error when attempting to
> deploy the subsequent war in Tomcat (as the jar ended up in the WAR file
> too)...
>
> Oct 11, 2011 10:42:30 AM org.apache.tomcat.util.digester.Digester
> endElement
> SEVERE: End event threw exception
> java.lang.NoSuchMethodException: org.apache.catalina.deploy.WebXml
> addServlet
>
> What is the class WebappClassLoader intended for? It looks like what
> Christopher's question is valid :-)
>> I have a question, though, since the default parent ClassLoader of
>> any ClassLoader /should/ be the current thread's context ClassLoader,
>> so none of the above code should be necessary.
>
> but the default ClassLoader used does not appear to be the one of the
> Webapp in question.
>
> thanks again,
> regards,
> Peter
>
>
>
> Christopher Schultz wrote:
>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
>>
>> Pid,
>>
>> On 10/10/2011 2:23 PM, Pid wrote:
>>> On 10/10/2011 18:51, Peter Lavin wrote:
>>>> Hi Filippo, tks for your reply.
>>>>
>>>> I'm not actually specifying any ClassLoader, perhaps I should? How
>>>> should I specify a ClassLoader to use when dynamically loading a class?
>>> You can pass one into the Constructor of your own classloader:
>>>
>>> public CustomClassloader(ClassLoader parent) { super(parent); }
>>
>> And to be perfectly explicit, OP should be doing this when
>> constructing their CustomClassLoader (presumably in a
>> ServletContextListener):
>>
>> CustomClassLoader cl = new
>> CustomClassLoader(Thread.currentThread().getContextClassLoader());
>>
>> This should allow Peter's ClassLoader to find superclass definitions
>> from the webapp's ClassLoader.
>>
>> I have a question, though, since the default parent ClassLoader of
>> any ClassLoader /should/ be the current thread's context ClassLoader,
>> so none of the above code should be necessary.
>>
>> Perhaps the CustomClassLoader is being initialized in a weird way
>> that does not make the above connection.
>>
>> - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10
>> (MingW32) Comment: Using GnuPG with Mozilla -
>> http://enigmail.mozdev.org/
>>
>> iEYEARECAAYFAk6TWHwACgkQ9CaO5/Lv0PD//gCgthcJU6rJ5pVjkJt3AOgEHqGq
>> EeYAnjq+VkKl/Ojx0QbP2lXPh5062bR6 =3mOs -----END PGP SIGNATURE-----
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For
>> additional commands, e-mail: users-h...@tomcat.apache.org
>>
>
signature.asc
Description: OpenPGP digital signature
