ClassLoader and ClassCastException

Question

ok, I have a Class named 'Lib' that I want to Load into the virtual machine from a file. I do this by extending ClassLoader and overloading the findClass() method to read the .class file through a FileInputStream.
Everything is fine until I try casting the 'Lib' object to a 'Lib' type. For example, I can do a
Object o = loadClass("Lib").newInstance();
but I cannot do a
Lib l = (Lib)loadClass("Lib").newInstance();
This also raises a new question: if you load a class dynamically during the execution of the program, how do you assign it to a new reference type so that you can use it?(i.e how do you make the 'Lib' type if you don't import the class? Incidently, I do import it and it still won't cast the object.)
I am making sure that the same class loader is loading all instances of the 'Lib' type, namely my(the extended) classloader, but it still won't let me cast. can anyone help??? thx.
Karl

Answer 1

Thanks for the comment Vlad. Here is the code I'm using, I verified that it is not being loaded by the bootstrap ClassLoader(default) as I moved it entirely out of the CLASSPATH.
Class myClass extens ClassLoader{
public void libInit(){
                        try{
                                        System.out.println("parent class loader: " + ClassLoader.getSystemClassLoader().toString());
                                        ClassLoader c = this.getClass().getClassLoader();
                                        System.out.println("this class loader: " + c.toString());
                                        Lib lib = (Lib)loadClass("Lib").newInstance();
                                        System.out.println("asserting Lib instance. " + lib.toString());
                                }catch(Exception e){
                                        System.err.println("error2: " + e.toString() + "  " + e.getMessage());
                public Class findClass(String name){
                        System.out.println("using my findClass()");
                        byte[] b = loadClassData(name);
                        return defineClass("Lib", b, 0, b.length);
                final Class findLoadedClasses(String name){
                         return null;
                        byte[] b = null;
                        try{
                                File f = new File("Libs","Lib.class");
                                FileInputStream fis = new FileInputStream(f);
                                int i = (int)f.length();
                                b = new byte;
System.out.println("boo " + i);
fis.read(b,0,i);
fis.close();
}catch(Exception e){
// Logger code goes here
System.err.println("error1: " + e.getMessage());
return b;
The above fails on the cast from the newInstance() method. In the above code is the first place in the program where I even reference a 'Lib' type.
Also, instead of using a 'Lib' type, how could I read a class file into a reference type? Is this what java.lang.ref is for? thanks.
Karl