Runtime error: java.lang

Question

I get the following error when running my class which is listed below(complies fine):
Exception in thread "main" java.lang.NoClassDefFoundError: FileComparer
It is also not just with this class because I tried to run a similar one and I got the same error. Anyone know what this means?
import java.io.*;
import java.net.*;
public class FileComparer
public static void main (String[] args)
     String line, file="http://condor.depaul.edu/~jpetlick/extra/224/display.txt";
     try
          int lineNum = 0;
          URL URLfile = new URL (file);
          InputStream input = URLfile.openStream();
          BufferedReader buffer = new BufferedReader(new InputStreamReader(input));
          line = buffer.readLine();
          while (line != null)
               line = buffer.readLine();
               lineNum++;
          System.out.println(line);
     catch (FileNotFoundException exception)
          System.out.println("The file " + file + " was not found.");
     catch (IOException exception)
          System.out.println(exception);
}

Answer 1

nevermind, I figured it out :)