code: public boolean isIgnoreClass(String className) {
  
      if (className == null) {
        return true;
      }
      className = className.replace('.', '/');
  
      if (processPackages.length > 0) {
        // use specific positive matching
        return specificMatching(className);
      }
  
      // we don't have specific packages to process so instead
      // we will ignore packages that we know we don't want
  
      // ignore $Proxy classes
      if (className.startsWith("$")) {
        return true;
      }
  
      int firstSlash = className.indexOf('/');
      if (firstSlash == -1) {
        return true;
      }
      String firstPackage = className.substring(0, firstSlash);
      if (ignoreOneLevel.contains(firstPackage)) {
        return true;
      }
      int secondSlash = className.indexOf('/', firstSlash + 1);
      if (secondSlash == -1) {
        return false;
      }
      String secondPackage = className.substring(0, secondSlash);
      if (ignoreTwoLevel.contains(secondPackage)) {
        return true;
      }
      int thirdSlash = className.indexOf('/', secondSlash + 1);
      if (thirdSlash == -1) {
        return false;
      }
      String thirdPackage = className.substring(0, thirdSlash);
      return ignoreThreeLevel.contains(thirdPackage);
    }
docs: Try to exclude JDK classes and known JDBC Drivers and Libraries.
  <p>
  We want to do this for performance reasons - that is skip checking for
  enhancement on classes that we know are not part of the application code
  and should not be enhanced.
  </p>
  
  @param className the className of the class being defined.
  
  @return true if this class should not be processed.