Creating a ClassLoader?

[Dillinger4]

This is an excerpt from an interesting artice i found inside a recent Java Developers Journal( Aug 2003 Vol:9 Issue:8) magazine.

The loadClass(String classname) method invokes the
findClass(String classname) method. Custom ClassLoaders
shoud override this method to provide a custom way of
locating and loading a Java class file.

Ok sounds easy enough but i have a few questions. Am i doing this right? How can i scope the size of the byte array to the number of bytes within the file? Once the class is returned from the classloader how can i execute it? More questions to come.........

import java.io.*;

 public class Loader extends ClassLoader{ 
 
  private byte[] b;  
   

  public Class findClass(String c) throws ClassNotFoundException{
    try{
     Scanner s = new Scanner(c); 
     this.b = s.getByteCode();
    }catch(IOException e){;} 
     return b.getClass();
  }
 }

 public class Scanner{
  
 private File res; 
  
 public Scanner(String r){ 
  res = new File(r); 

 }
 public byte[] getByteCode() throws IOException{
  BufferedInputStream buff; 
   buff = new BufferedInputStream(new FileInputStream(res));
   byte[] b = new byte[5000];
     long bytesread = 0;  
   while(true){
     bytesread = buff.read(b); 
     if(bytesread < 0) break;
    
   }  
    return b; 
  }
 }