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);
}
p
> Filippo Machi wrote:
>> Ciao Piter,
>> usually class loaders are arranged unto a hierarchy, who's the parente
>> classloader of the one you're using to define the class fronte the byte
>> array? It should've be the classloader whose scope us your webapp..
>> Hth
>> Fil
>> Il giorno 10/ott/2011 19.27, "Peter Lavin" <lav...@cs.tcd.ie> ha scritto:
>>
>>> Dear Users,
>>> I am running web-services (developed in CXF) in a Tomcat 7.0.14 server,
>>> Java version "1.6.0_17", OS, Linux <hostname> 2.6.18-238.9.1.el5 #1
>>> SMP Tue
>>> Apr 12 18:10:13 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
>>>
>>>
>>> Part of my service code takes a byte array and defines a class using its
>>> contents which was not previously loaded in the JVM, code snippet as
>>> follows...
>>>
>>> Class<?> c = defineClass(name, byArray, 0, byArray.length);
>>>
>>> This code is in a class which extends java.lang.ClassLoader.
>>>
>>> The class represented by the byte array btArray is a class which
>>> extends a
>>> super class.
>>>
>>> Background...
>>> * Dynamic loading of a class this way works in the IDE (Eclipse)
>>> when not
>>> running in a Tomcat server.
>>> * The super class from which the loaded class extends is included in
>>> the
>>> war file, the files are present on the tomcat server.
>>> * When loading a class which does not extend a super class (no
>>> inheritance), the above code works fine within the service in Tomcat.
>>> * When using a class which implements an interface an interface but no
>>> inheritance, it also fails (with the following exception).
>>> * When using a class which implements an interface which is in
>>> java.io.*,
>>> e.g. Serializable, the class loads ok within the Tomcat server.
>>>
>>> I have tried to use WebappClassloader, but cannot get the service to
>>> deploy
>>> when this class is imported from catalina.jar.
>>>
>>> Relevant parts of the error output is pasted here...
>>>
>>> WARNING: Application {http://peteragent.sga.org/}**
>>> AgentServiceImplService#{http:**//peteragent.sga.org/}process<http://peteragent.sga.org/%7DAgentServiceImplService#%7Bhttp://peteragent.sga.org/%7Dprocess>has
>>> thrown exception, unwinding now
>>> org.apache.cxf.interceptor.**Fault:
>>> common/core/**AbstractServiceProvider
>>> at org.apache.cxf.service.**invoker.AbstractInvoker.**
>>> createFault(AbstractInvoker.**java:155)
>>> [...abridgment...]
>>> Caused by: java.lang.**NoClassDefFoundError: common/core/**
>>> AbstractServiceProvider
>>> at java.lang.ClassLoader.**defineClass1(Native Method)
>>> at java.lang.ClassLoader.**defineClass(ClassLoader.java:**632)
>>> at java.lang.ClassLoader.**defineClass(ClassLoader.java:**478)
>>> at common.utilities.ClassLoading.**FileClassLoader.loadClass(**
>>> FileClassLoader.java:24)
>>> [end]
>>>
>>>
>>> My questions, has anyone also had this problem?
>>> Is WebappClassLoader designed to overcome this problem?
>>> Does anyone know why the class loads, but the JVM/ClassLoader is
>>> unable to
>>> find the super classes (although they are present). I'm aware that
>>> Tomcat
>>> uses a different ClassLoader for each webapp, but the required classes
>>> should be present in the ClassLoader of the webapp in question as
>>> they are
>>> in the war, and are in the file
>>> .../webapps/serviceName/WEB-**INF/classes/
>>> directory.
>>>
>>>
>>> with thanks,
>>> Peter
>>>
>>>
>>> --
>>> with best regards,
>>> Peter Lavin,
>>> PhD Candidate,
>>> Computer Architecture & Grid Research Group,
>>> Lloyd Institute, 005,
>>> Trinity College Dublin, Ireland.
>>> +353 1 8961536
>>>
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>>>
>>>
>>
>
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