code: public Map<String, Class> mapAllClasses(String uri) throws IOException, ClassNotFoundException {
          Map<String, Class> classes = new HashMap<>();
          Map<String, String> map = mapAllStrings(uri);
          for (Iterator iterator = map.entrySet().iterator(); iterator.hasNext();) {
              Map.Entry entry = (Map.Entry) iterator.next();
              String string = (String) entry.getKey();
              String className = (String) entry.getValue();
              Class clazz = classLoader.loadClass(className);
              classes.put(string, clazz);
          }
          return classes;
      }
docs: Executes mapAllStrings assuming the value of each entry in the
  map is the name of a class that should be loaded.
  <p/>
  Any class that cannot be loaded will be cause an exception to be thrown.
  <p/>
  Example classpath:
  <p/>
  META-INF/xmlparsers/xerces
  META-INF/xmlparsers/crimson
  <p/>
  ResourceFinder finder = new ResourceFinder("META-INF/");
  Map map = finder.mapAvailableStrings("xmlparsers");
  map.contains("xerces");  // true
  map.contains("crimson");  // true
  Class xercesClass = map.get("xerces");
  Class crimsonClass = map.get("crimson");
  
  @param uri
  @return
  @throws IOException
  @throws ClassNotFoundException