How to quickly check if a class exists

Question

I want to do something like this:

  try {
    Class.forName( "your.fqdn.class.name" );
  } catch( ClassNotFoundException e ) {
  //my class isn't there!
}

However I need to do it far more quickly. Execution time of Class.forName(name) is about 200ms for me and this is not good enough.

Is there a faster way of doing the same thing?