Extending a ClassLoader's Resource-Finding Functionality

Question

First Question:
Is there a difference between:
<class_name>.class.getResource()
and
this.getClass().getResource()
Is one done natively? How does the VM see these two - as equivalent?
Second Question:
I know that when getClass().getResource() (or the other) is called, that it delegates the check to the Class's ClassLoader. So really the call is to the ClassLoader. So when you normally do a call for getResource() it just creates a path by changing the class's package dots into "/" and looking in the folder structure. Here's what I want to do:
1. Have XML config files for Objects in a package
a. Have these XML files available either through Http, file, etc.
2. Be able to tie the domain address to the ProtectionDomain of a package
   EXAMPLE
        If I have "http://www.site.com/Person.cfg" as the config file for
        the object of class: com.site.dept.Person, then when the Person
        object calls: this.getClass().getResource( "http://www.site.com/Person.cfg" );
        the resource should be found (and as well, if they call:
        this.getClass().getResource( "http://www.evil.com/Person.cfg" ) it
        should return null ). Also, just as with any resource actually in
        the folder: com/site/dept (inside the jar or whatever), it will be
        a part of that ProtectionDomain and have the same security settings
        as a file in that folder would have.Does anyone have any ideas on the best way to do this? I am obviously sub-classing the ClassLoader (which I've done), and already I have set up my ClassLoader to be able to load either http (or any other protocol) files, as well as normal system files. (NOTE: URLClassLoader does NOT do this. Give it a try: myURLClassLoader.getResourceAsStream( "http://..." ) and you'll find it returns null)
I want this to be as clean and secure as possible. I also know that I should delegate to the super class (URLClassLoader) as much as possible. So I'm at a loss as to what's the best way to tie the http addresses (or other protocol addresses) to the correct package spots. Just to give you all more info, when I create the classloader I can pass it the info of what address is supposed to go with what object. So maybe something like this:
   <ConfigResource>
      <Location>"http://www.site.com/Person.cfg"</Location>
      <Object>com.site.dept.Person</Object>
   </ConfigResource>Thanks and please let me know if anything here needs more explaining!
-Robert

Answer 1

Let me try this
First Question:
Is there a difference between:
<class_name>.class.getResource()
and
this.getClass().getResource()
Is one done natively? How does the VM see these two
wo - as equivalent?
To chech whether this (getResource()) is native or not you require to refer the source code of the java.lang.Class file.In fact there it is not defined as native method It returns URL object.But within the implementation of getResource you can see the getClassLoader0() method whuch returns the classLoader and the getClassLoader0() is a native type.
They are not equivalent,there can be multiple instances of the same object loaded by different Classloaders then your first type will be obtained to get the same objects instance in the different classLoader.Hope you get what I am trying,All this I am expaining as per my undestanding......So I hope some one really try to rectify it if I am describing it wrong....
Your second Question :
For that what you are doing is fine by inheriting the ClassLoader features but then sun have come up with the URLClassLoader where many more features are implemented which we have to implement when only the classloader is inherited.For the application specified where you are trying to load the object by the HTTP protocol/file protocol I feel you can rely on the URLCLassLoader functionality....But if you want more like checking in the repository,loading from database,cache etc you require to implement all this in both the Classes......in defineClass()......For better implementation of ClassLoader you can see the source code of the AdaptiveClassLoader class which is implemented by the Tomcat .........
Hope this helps......
regards vicky