Loading resources with customized class loader

Question

I have a customized classloader that keeps classes and resources in a table in byte[] form. It works fine as far as loading classes go, I just call defineClass with the byte array corresponding to the class. My problem is how to load resources. I already have the resource data in the table, which you'd think would be a good thing, but the method that has to be overridden (getResource or findResource) is supposed to return an URL to the resource. The only way I can think of to do that is to write the data to a file and return an URL to that file, but I don't even wanna touch that solution with a nine foot stick. Surely there must be a better way!?

Answer 1

Usually, when your resources are in a custom source, you create and implement your own URL protocol (like jar:). This is done by creating your own java.net.URLStreamHandler and java.net.URLConnection implementations. You can peruse the jar implementation in sun.net.www.protocol.jar as a good example.
Once you have your own protocol that knows how to get to your resource file and how to identify and extract a resource, you simply use that protocol in the URLs returned by your ClassLoader. The resource URLs can then be used as you would normally use any URL.
A tutorial describing how all of this works, and how to implement your own is at:
http://developer.java.sun.com/developer/onlineTraining/protocolhandlers/
I hope you find this of some help.